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Crash Course, Syntax 2 - Trees: Crash Course Linguistics #4

Syntax 2 - Trees: Crash Course Linguistics #4

Hi, I'm Taylor and welcome to Crash Course Linguistics!

In episode 3, we learned about how to test which parts of a sentence are constituents, or closely-related subgroups of words.

So in the sentence, “Taylor sees the rabbit,” we know "the rabbit" is one such constituent

because we can substitute for it a single word or pronoun, like "Gavagai" or "them".

And "sees the rabbit' is another, slightly larger constituent, because we can move the whole thing up to the beginning of the sentence in a cleft construction:

"it's seeing the rabbit that Taylor does".

Now, we want to take it a step deeper.

Let's figure out a way to keep track of these groupings, and extract some rules that could help us find patterns between lots of different sentences.

[THEME MUSIC]

A simple way to keep track of different parts of sentences is by drawing connections between words.

For example, we could draw circles around each constituent.

But circles get really big, really quickly as our sentences get longer.

Or, we could draw brackets around each of the constituents.

Brackets are nice and compact, but they can be hard to easily scan and understand at a glance.

So, instead, linguists often represent the structural relationships between words using a tree structure diagram, sort of like a family tree with nodes and branches.

Tree diagrams strike a nice balance between being understandable and taking up a reasonable amount of space.

The nodes represent links between constituents, so it's useful to label them.

That helps us compare the tree diagrams across various sentences and track the different phrases in the sentence, too.

A phrase is a constituent that's sorta mid sized.

It's less than a full sentence but often more than a single word.

In this video we're going to meet some of the common phrases that are the basis of English grammar.

For example, the difference between the phrases "sees the rabbit" and just "the rabbit" is that "sees the rabbit" has a verb in it.

So we can call "sees the rabbit" a verb phrase.

Using the substitution test we talked about in the previous video, we can swap the positions of "Taylor" and "the rabbit" in this sentence.

So they should both be the same kind of phrase.

Since both of these phrases have a noun in them, we'll call them noun phrases.

The word "the", by the way, is part of a class of words that linguists call determiners, which also includes words like "a," "this," "my," "one," and "every."

Determiners help us figure out which specific instance of a specific noun we're talking about.

There's one theory of syntax that actually argues there are determiner phrases as well as noun phrases.

Either way, these small words do a big job.

So, let's label our tree with the phrases and the word classes to keep track of all of this information.

And the whole thing, as we already know, is a sentence.

Writing out "noun phrase" and "verb phrase" every time gets kind of tedious, so linguists generally abbreviate these as NP and VP.

And the same goes with N for noun, V for verb and S for sentence, plus Det for determiner.

Tree diagrams let us see the predicate relationship we talked about in the last episode.

The verb and the object noun phrase are both together within the VP.

Even in languages that put their words in a different order, the verb and the object still have this closer relationship.

Let's take Japanese for example.

In Japanese, the verb comes at the end of the sentence.

The verb is still in the same phrase, the verb phrase, as the object, so we can represent this in a tree structure diagram by just giving the VP node a little twist.

Going back to English now, here's another sentence: Gavagai ate my cake.

This new sentence has completely different words from the first one, but it has the exact same structure, so its tree structure diagram looks the same.

We can make a lot of sentences from just a few basic bits of structure.

And this leads us to an interesting puzzle.

Let's try to figure out all of the possible structures for sentences in English.

In other words, let's try to make a grammar of English.

A grammar is a description of how sentences go together in a language.

We could use a grammar to start to teach machines to understand English, or to compare the rules of English to those of another language.

A grammar isn't necessarily what's actually going on in your head when you're saying a sentence.

That's still an open question that linguists are researching.

And while we'll be focusing on a grammar of English here, every language has one.

Making a grammar is actually a pretty big challenge.

Let's start out with a few sentences and figure out how to describe their structures.

Taylor sees the rabbit.

The rabbit ate cake.

And, Gavagai hopped.

First we notice that we can split each sentence into two pieces, and we can mix and match the front half and the back half.

We have “Taylor,” “the rabbit,” and “Gavagai” on one side and “sees the rabbit,” “ate cake,” and “hopped” on the other.

This structure predicts that "Taylor hopped" and "Taylor ate cake" and "Gavagai sees the rabbit" should be okay sentences, even though they're not on our original list.

Based on my linguistic intuitions as an English speaker, that's a good prediction and is part of our grammar!

We've established that sentences contain two parts.

But what if we split those sentences up like this instead?

This predicts that the sentences "Gavagai ate rabbit ate cake" and "the my cake" should be possible, and we know as English speakers that they're not!

We'd expect some groupings to fail like this in any language we tried.

So in our grammar of English so far, these sentences contain two parts, but it also matters what those two parts are.

Let's go back to our list that works, and highlight the nouns, verbs, and determiners in different colors.

So for “Taylor sees the rabbit,” we'll make “taylor” and “rabbit” red for noun, “sees” blue for verb, and “the” green for determiner.

Based on this, we could write a couple rules for English grammar.

First, we can say that a sentence in English is made up of two parts: a noun phrase plus a verb phrase.

A noun phrase is made up of a determiner plus a noun.

And a verb phrase is made up of a verb plus a noun phrase.

But even though those rules are a good start, they still need a few tweaks.

Not all of our noun phrases have a determiner in them.

Sometimes it's "the rabbit" but other times it's just "cake".

And some of our verb phrases don't have a noun phrase in them, either.

Sometimes it's "sees the rabbit" or "ate cake" but other times it's just "hopped".

So we need to indicate that certain parts of these rules are optional, which we can do using parentheses.

It has a nice effect.

The only thing that's absolutely required in a noun phrase is a noun, and the only thing that's required in a verb phrase is a verb.

We call this required piece, the part that the phrase is named after, the head, and the less important additions the complement.

There are plenty more things we can add to a sentence, which starts to make a grammar even more complicated.

For instance, take these ones:

The rabbit with a scarf hopped.

And Gavagai ate cake on the moon.

We've added two new phrases: “with a scarf” and “on the moon.”

These phrases contain a determiner and a noun, but they also contain a preposition, a word that shows the relationship of a noun phrase to the rest of the sentence.

So now we can make a rule for a prepositional phrase, which contains a preposition as the head and a noun phrase as the complement.

We also need to refine our rules for noun phrases and verb phrases to allow for optional prepositional phrases.

So far, our grammar contains just four rules.

But it's already really powerful.

To find out how, let's go into the Thought Bubble.

Hey look!

Gav and I are inside a thought bubble.

Let's go into another thought bubble.

Cool, we're inside a thought bubble inside a thought bubble!

Let's go deeper!

Now, we're inside a thought bubble inside a thought bubble inside a thought bubble.

We could just keep going!

We might get bored or run out of space on the screen or get cut off by YouTube's time limits, but in theory, we could just keep embedding thought bubbles inside thought bubbles...forever.

Uh, let's pop a few of these thought bubbles to get some more breathing room.

Okay, leave thought bubble.

And….leave thought bubble.

Ok, we're back in a normal single bubble!

Thought bubbles have the property of recursion.

We can embed thought bubbles inside thought bubbles forever.

Language is also recursive. Let's take the phrase "inside a thought bubble".

"Inside" is a preposition, so this is a prepositional phrase.

And "a thought bubble" is a noun phrase.

But inside this noun phrase "a thought bubble" we can add another prepositional phrase.

Let's say it's also "inside a thought bubble".

And we can keep going.

In fact, we already did, when we were describing the recursive thought bubbles in the first place.

We don't always have to embed the exact same words.

Recursion just means that we can build structures inside other structures.

For instance, the Rabbit on the moon in the solar system in the milky way in the universe on Friday hopped.

There Gav goes!

Thanks, Thought Bubble!

(And thought bubble, and thought bubble!)

Our simplified little set of four grammar rules is powerful enough for recursion, but there are also some things missing:

adjectives like "big" or "purple", adverbs like "quickly", pronouns like "you" or "me".

Sadly, this video does not actually contain infinite recursive space,

but now that we're thinking like linguists, we can use our knowledge of language to continue to build up a more complete set of rules.

This is just the start!

But even with just four rules, we can see that sometimes completely different words have the same linguistic structure.

Other times, the same words have different linguistic structures.

We can see these similarities and differences by looking at language from the perspective of syntax.

Let's take these two sentences.

“Time flies like an arrow” means that the concept of time is fast, like an arrow is fast.

“Fruit flies like a banana” means that these small insects are fond of fruit.

Both of these sentences have "flies" and "like" in them, but these words have different structural relationships with the rest of the sentence.

In this first tree, "flies" is the verb, and "like" is a preposition.

In this second tree, "flies" is part of the noun phrase and "like" is the verb.

We can represent that difference by drawing diagrams.

Don't stress about the triangles.

Linguists use triangles within a tree to save space and represent constituents that are not the focus of what we're talking about.

But we can see how these shared words occupy different parts of each tree.

Or take the song about the mythical "One-eyed one-horn flying purple people eater".

This could mean a song about a creature that eats any kind of people and has one eye, one horn, flies, and is purple.

Or it could be about a creature that eats one-eyed, one-horned, flying purple people.

Or something in between.

Maybe a one-eyed, one-horn creature that eats flying purple people?

Some of these beasts are a lot more dangerous than others.

Throughout this episode, we've been using rules and tree diagrams as a fairly simple way of representing the structure of sentences.

But there are lots of other ways of representing the same sentences.

There are many theories of syntax which have different ways of representing grammatical structures, each with their advantages and limitations.

And there are some grammatical structures that syntacticians haven't even figured out how to represent yet!

So far, we've seen sentences with absurd meanings but reasonable grammar.

Next time on Crash Course Linguistics, we'll go deeper into meaning itself.

Thanks for watching this episode of Crash Course Linguistics.

If you want to help keep all Crash Course free for everybody, forever, you can join our community on Patreon.

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Syntax 2 - Trees: Crash Course Linguistics #4 句法|||| |Arbres syntaxiques|Crash Course Linguistique|Cours| Syntax|||| ||||언어학(1) |||Курс| Syntax 2 - Bäume: Crashkurs Linguistik #4 Syntax 2 - Trees: Crash Course Linguistics #4 Sintaxis 2 - Árboles: Curso acelerado de lingüística nº 4 Syntaxe 2 - Arbres : Cours accéléré de linguistique #4 Sintassi 2 - Alberi: Corso accelerato di linguistica #4 構文2 - 木:クラッシュコース言語学 第4回 구문 2 - 나무: 크래시 코스 언어학 #4 Syntaxis 2 - Bomen: Spoedcursus taalkunde #4 Składnia 2 - Drzewa: Crash Course Linguistics #4 Sintaxe 2 - Árvores: Curso rápido de linguística #4 Синтаксис 2 - Деревья: Краткий курс лингвистики #4 Syntax 2 - Träd: Snabbkurs i lingvistik #4 Sözdizimi 2 - Ağaçlar: Crash Course Dilbilim #4 Синтаксис 2 - Дерева: Прискорений курс лінгвістики #4 语法 2 - 树:语言学速成班 #4 語法 2 - 樹:語言學速成課程 #4

Hi, I'm Taylor and welcome to Crash Course Linguistics! Hi, I'm Taylor and welcome to Crash Course Linguistics! Merhaba, ben Taylor ve Crash Course Linguistics'e hoş geldiniz!

In episode 3, we learned about how to test which parts of a sentence are constituents, or closely-related subgroups of words. ||||||||какие||||||составные части|||связанными|подгруппы|| ||||||||||||||constituants||étroitement|étroitement liés||| ||||||||which||||||subgroups of words|||related|subgroups|| ||||||||||||||thành phần|||||| ||||||||||||||Konstituenten|||||| ||||||||||||||składniki|||||| No episódio 3, aprendemos a testar que partes de uma frase são constituintes, ou subgrupos de palavras estreitamente relacionadas. В эпизоде 3 мы узнали о том, как проверить, какие части предложения являются составными, или тесно связанными подгруппами слов. Bölüm 3'te, bir cümlenin hangi kısımlarının bileşen veya birbiriyle yakından ilişkili kelime alt grupları olduğunu nasıl test edeceğimizi öğrendik. 在第 3 集中,我们学习了如何测试句子的哪些部分是成分,或密切相关的词组。

So in the sentence, “Taylor sees the rabbit,” we know "the rabbit" is one such constituent ||||||||||||||такой|составная часть ||||||||||||||tel|élément de phrase ||||||||||||||solche|Satzglied |||||||||||||||phrase or element |||||||||||||||thành phần Assim, na frase "O Taylor vê o coelho", sabemos que "o coelho" é um desses constituintes Так, в предложении "Тейлор видит кролика" мы знаем, что "кролик" - это одна из таких составляющих. Dolayısıyla, "Taylor tavşanı görür" cümlesinde "tavşan "ın böyle bir bileşen olduğunu biliyoruz

because we can substitute for it a single word or pronoun, like "Gavagai" or "them". |||заменить||||||||||| parce que|||||||||||||| |||ersetzen|||||||||Gavagai(1)|| |||replace||||||||||| porque podemos substituí-la por uma única palavra ou pronome, como "Gavagai" ou "eles". потому что мы можем заменить его одним словом или местоимением, например, "Гавагай" или "они".

And "sees the rabbit' is another, slightly larger constituent, because we can move the whole thing up to the beginning of the sentence in a cleft construction: ||||||légèrement|plus grand|||||||ensemble complet|élément complet|au début|||||||||mise en relief| and||||||slightly||||||||entire|||||||||||emphasized sentence structure|construction ||||||||Konstituente|||||||||||||||||Kleinsatz| |||||||||||||||||||||||||costruzione cleft| |||||||||||||||||||||||||rozdzielonej| E "vedere il coniglio" è un altro costituente, leggermente più grande, perché possiamo spostare tutta la cosa all'inizio della frase in una costruzione cleft: А "sees the rabbit" - это еще одна, чуть более крупная составляющая, потому что мы можем перенести все это в начало предложения в расщепленной конструкции:

"it's seeing the rabbit that Taylor does". "C'est le fait de voir le lapin que fait Taylor. "è vedere il coniglio che fa Taylor". "это видеть кролика, которого делает Тейлор".

Now, we want to take it a step deeper. ||||||||un peu plus loin ||||||||deeper Nous voulons maintenant aller plus loin. Ora vogliamo fare un passo più in profondità. Agora, queremos ir um pouco mais longe. Теперь мы хотим сделать еще один шаг вглубь.

Let's figure out a way to keep track of these groupings, and extract some rules that could help us find patterns between lots of different sentences. ||||||||||||||||||||motifs||||| ||||||||||categories||derive||||||||||||| Trouvons un moyen de garder une trace de ces regroupements et d'extraire quelques règles qui pourraient nous aider à trouver des modèles entre un grand nombre de phrases différentes. Давайте придумаем способ отслеживать эти группировки и выведем несколько правил, которые помогут нам найти закономерности между множеством различных предложений.

[THEME MUSIC]

A simple way to keep track of different parts of sentences is by drawing connections between words. Uma forma simples de manter o controlo das diferentes partes das frases é estabelecer ligações entre as palavras. Простой способ отслеживать различные части предложений - рисовать связи между словами.

For example, we could draw circles around each constituent. for|||||||| Por exemplo, podemos desenhar círculos à volta de cada eleitor.

But circles get really big, really quickly as our sentences get longer. Mas os círculos tornam-se muito grandes, muito rapidamente, à medida que as nossas frases se tornam mais longas. Но круги становятся очень большими, очень быстро, когда наши предложения становятся длиннее.

Or, we could draw brackets around each of the constituents. |||||||||parts Ou, podemos desenhar parênteses à volta de cada um dos constituintes. Или мы можем нарисовать скобки вокруг каждой из составляющих.

Brackets are nice and compact, but they can be hard to easily scan and understand at a glance. dấu ngoặc||||||||||||||||| ||||concise||||||||read quickly|||||glance Le parentesi sono belle e compatte, ma possono essere difficili da scansionare e comprendere a colpo d'occhio. Os parênteses são bonitos e compactos, mas podem ser difíceis de digitalizar e compreender num relance. Скобки - это красиво и компактно, но их трудно отсканировать и понять с первого взгляда.

So, instead, linguists often represent the structural relationships between words using a tree structure diagram, sort of like a family tree with nodes and branches. ||||||||||||||||||||||nút||cành ||||||||||||||tree structure||||||||points|| ||||||||||||||||||||||nodi|| Quindi, invece, i linguisti spesso rappresentano le relazioni strutturali tra le parole utilizzando un diagramma a struttura ad albero, un po' come un albero genealogico con nodi e rami. Por isso, em vez disso, os linguistas representam frequentemente as relações estruturais entre as palavras através de um diagrama de estrutura em árvore, uma espécie de árvore genealógica com nós e ramos. Поэтому лингвисты часто представляют структурные отношения между словами с помощью древовидной диаграммы, похожей на семейное дерево с узлами и ветвями.

Tree diagrams strike a nice balance between being understandable and taking up a reasonable amount of space. |Tree diagrams|provide|||||||||||||| ||apresentam||||||compreensíveis|||||||| I diagrammi ad albero colgono un buon equilibrio tra essere comprensibili e occupare una quantità ragionevole di spazio. Os diagramas em árvore atingem um bom equilíbrio entre serem compreensíveis e ocuparem uma quantidade razoável de espaço. Древовидные диаграммы - это хороший баланс между понятностью и разумным объемом.

The nodes represent links between constituents, so it's useful to label them. |||||||||||the nodes ||||||||||etichettare| De knooppunten vertegenwoordigen koppelingen tussen componenten, dus het is handig om ze te labelen. Os nós representam ligações entre constituintes, pelo que é útil rotulá-los. Узлы представляют собой связи между компонентами, поэтому их полезно обозначить.

That helps us compare the tree diagrams across various sentences and track the different phrases in the sentence, too. Isto ajuda-nos a comparar os diagramas de árvore em várias frases e a seguir as diferentes frases da frase. Это помогает нам сравнивать древовидные диаграммы в разных предложениях и отслеживать различные фразы в предложении.

A phrase is a constituent that's sorta mid sized. ||||part of speech||kind of|| ||||||trochę|| ||||||meio que|| Una frase è un costituente che è piuttosto di dimensioni medie. Uma frase é um constituinte que é mais ou menos de tamanho médio. Фраза - это составная часть, которая является чем-то вроде среднего размера.

It's less than a full sentence but often more than a single word. È meno di una frase completa ma spesso più di una singola parola.

In this video we're going to meet some of the common phrases that are the basis of English grammar. In questo video incontreremo alcune delle frasi comuni che sono alla base della grammatica inglese.

For example, the difference between the phrases "sees the rabbit" and just "the rabbit" is that "sees the rabbit" has a verb in it. de|exemplu|(1) diferența|diferența|între|expresiile|expresiile|vede|iepurele|iepure|și|doar|iepurele|iepurele|este|că|vede||iepurele||||| Например, разница между фразами "видит кролика" и просто "кролик" в том, что в "видит кролика" есть глагол.

So we can call "sees the rabbit" a verb phrase.

Using the substitution test we talked about in the previous video, we can swap the positions of "Taylor" and "the rabbit" in this sentence. ||substitution test||||||||||||||||||||| |||||||||||noi||schimba|||||||||| |||||||||||||trocar|||||||||| Используя тест на подстановку, о котором мы говорили в предыдущем видео, мы можем поменять местами слова "Taylor" и "the rabbit" в этом предложении.

So they should both be the same kind of phrase. ||ar trebui|amândouă||||||

Since both of these phrases have a noun in them, we'll call them noun phrases. |||||||||||numim|||

The word "the", by the way, is part of a class of words that linguists call determiners, which also includes words like "a," "this," "my," "one," and "every." ||||||||||||||||từ hạn định||||||||||| ||||||||||||||||determiners||||||||||| ||||||||||||||||determinatów||||||||||| ||||||||||||||||os determinantes||||||||||| The word "the", by the way, is part of a class of words that linguists call determiners, which also includes words like "a," "this," "my," "one," and "every."

Determiners help us figure out which specific instance of a specific noun we're talking about. 限定词|||||||||||||| Articles and quantifiers||||||||||||||

There's one theory of syntax that actually argues there are determiner phrases as well as noun phrases. ||||cú pháp|||||||||||| ||teorie|||||||||||||| |||||||claims|||determiner phrases|||||| ||||||||||um determinante|||||| Er is één syntaxistheorie die stelt dat er zowel bepalende als zelfstandige naamwoorden zijn.

Either way, these small words do a big job. In any||||||||

So, let's label our tree with the phrases and the word classes to keep track of all of this information. ||rotular|||||||||||||||||

And the whole thing, as we already know, is a sentence.

Writing out "noun phrase" and "verb phrase" every time gets kind of tedious, so linguists generally abbreviate these as NP and VP. ||||||||||||mühsam||||||||| ||||||||||||boring and repetitive||||shorten|||noun phrase||verb phrase ||||||||||||noioso||||||||| ||||||||||||nudne|||||||||

And the same goes with N for noun, V for verb and S for sentence, plus Det for determiner. ||||||||||||||||determiner||determiner one

Tree diagrams let us see the predicate relationship we talked about in the last episode. ||||||đối tượng|||||||| |tree diagrams|||||verb phrase|||||||| ||||||predykat||||||||

The verb and the object noun phrase are both together within the VP. ||||object noun||||||||

Even in languages that put their words in a different order, the verb and the object still have this closer relationship. |||||||||||||||noun phrase|||||

Let's take Japanese for example.

In Japanese, the verb comes at the end of the sentence.

The verb is still in the same phrase, the verb phrase, as the object, so we can represent this in a tree structure diagram by just giving the VP node a little twist. |||||||||||||||||||||||||||||node one||| ||||||||||||||||||||||||||||||||uma torção

Going back to English now, here's another sentence: Gavagai ate my cake.

This new sentence has completely different words from the first one, but it has the exact same structure, so its tree structure diagram looks the same.

We can make a lot of sentences from just a few basic bits of structure.

And this leads us to an interesting puzzle.

Let's try to figure out all of the possible structures for sentences in English.

In other words, let's try to make a grammar of English.

A grammar is a description of how sentences go together in a language.

We could use a grammar to start to teach machines to understand English, or to compare the rules of English to those of another language.

A grammar isn't necessarily what's actually going on in your head when you're saying a sentence.

That's still an open question that linguists are researching. ||||||||investigating

And while we'll be focusing on a grammar of English here, every language has one.

Making a grammar is actually a pretty big challenge.

Let's start out with a few sentences and figure out how to describe their structures.

Taylor sees the rabbit.

The rabbit ate cake.

And, Gavagai hopped. ||jumped ||pulou

First we notice that we can split each sentence into two pieces, and we can mix and match the front half and the back half. Initially|||||||||||||||||||||||| ||||||dividir||||||||||||||||||

We have “Taylor,” “the rabbit,” and “Gavagai” on one side and “sees the rabbit,” “ate cake,” and “hopped” on the other. ||||o coelho||||||||||||||||

This structure predicts that "Taylor hopped" and "Taylor ate cake" and "Gavagai sees the rabbit" should be okay sentences, even though they're not on our original list.

Based on my linguistic intuitions as an English speaker, that's a good prediction and is part of our grammar! ||||feelings||||||||||||||

We've established that sentences contain two parts. |determined|||||

But what if we split those sentences up like this instead?

This predicts that the sentences "Gavagai ate rabbit ate cake" and "the my cake" should be possible, and we know as English speakers that they're not!

We'd expect some groupings to fail like this in any language we tried.

So in our grammar of English so far, these sentences contain two parts, but it also matters what those two parts are.

Let's go back to our list that works, and highlight the nouns, verbs, and determiners in different colors. |||||||||highlight||||||||

So for “Taylor sees the rabbit,” we'll make “taylor” and “rabbit” red for noun, “sees” blue for verb, and “the” green for determiner.

Based on this, we could write a couple rules for English grammar.

First, we can say that a sentence in English is made up of two parts: a noun phrase plus a verb phrase.

A noun phrase is made up of a determiner plus a noun.

And a verb phrase is made up of a verb plus a noun phrase.

But even though those rules are a good start, they still need a few tweaks. ||||||||||||||adjustments ||||||||||||||ajustes

Not all of our noun phrases have a determiner in them.

Sometimes it's "the rabbit" but other times it's just "cake". ||||||||просто|

And some of our verb phrases don't have a noun phrase in them, either.

Sometimes it's "sees the rabbit" or "ate cake" but other times it's just "hopped".

So we need to indicate that certain parts of these rules are optional, which we can do using parentheses. ||||||||||||||||||footnote reference ||||||||||||||||||parênteses

It has a nice effect.

The only thing that's absolutely required in a noun phrase is a noun, and the only thing that's required in a verb phrase is a verb.

We call this required piece, the part that the phrase is named after, the head, and the less important additions the complement. |||||||||||||||||||less important additions||complementary part We noemen dit vereiste stuk, het deel waarnaar de zin is vernoemd, het hoofd, en de minder belangrijke toevoegingen het complement.

There are plenty more things we can add to a sentence, which starts to make a grammar even more complicated. ||many|||||||||||||||||

For instance, take these ones:

The rabbit with a scarf hopped. ||||cachecol|

And Gavagai ate cake on the moon.

We've added two new phrases: “with a scarf” and “on the moon.”

These phrases contain a determiner and a noun, but they also contain a preposition, a word that shows the relationship of a noun phrase to the rest of the sentence. ||||article|||||||||relationship word||||||||||||||||

So now we can make a rule for a prepositional phrase, which contains a preposition as the head and a noun phrase as the complement. |||||||||prepositional phrase|||||preposition||||||||||

We also need to refine our rules for noun phrases and verb phrases to allow for optional prepositional phrases. |||||||||||||||||giới từ| ||||improve||||||||||||||

So far, our grammar contains just four rules.

But it's already really powerful.

To find out how, let's go into the Thought Bubble.

Hey look!

Gav and I are inside a thought bubble. Gav|||||||

Let's go into another thought bubble.

Cool, we're inside a thought bubble inside a thought bubble!

Let's go deeper!

Now, we're inside a thought bubble inside a thought bubble inside a thought bubble.

We could just keep going!

We might get bored or run out of space on the screen or get cut off by YouTube's time limits, but in theory, we could just keep embedding thought bubbles inside thought bubbles...forever. |||||||||||||||||||||||||||nhúng|||||| |||||||||||||||||YouTube's||||||||||inserting|||||| ||||||||espacio en pantalla||||||interrumpidos||||||||teoría en teoría|||||||||||

Uh, let's pop a few of these thought bubbles to get some more breathing room. Um||burst|||||||||||space to think|

Okay, leave thought bubble.

And….leave thought bubble. And then|||

Ok, we're back in a normal single bubble!

Thought bubbles have the property of recursion. ||||||đệ quy ||||||Rekursion ||||||level one ||||||递归

We can embed thought bubbles inside thought bubbles forever. ||insert||||||

Language is also recursive. Let's take the phrase "inside a thought bubble". |||đệ quy|||||||| |||level 1||||||||

"Inside" is a preposition, so this is a prepositional phrase. ||||||||giới từ| "Binnen" is een voorzetsel, dus dit is een voorzetsel.

And "a thought bubble" is a noun phrase.

But inside this noun phrase "a thought bubble" we can add another prepositional phrase.

Let's say it's also "inside a thought bubble".

And we can keep going.

In fact, we already did, when we were describing the recursive thought bubbles in the first place.

We don't always have to embed the exact same words.

Recursion just means that we can build structures inside other structures.

For instance, the Rabbit on the moon in the solar system in the milky way in the universe on Friday hopped. |||||||||||||Milky Way|||||||

There Gav goes!

Thanks, Thought Bubble!

(And thought bubble, and thought bubble!)

Our simplified little set of four grammar rules is powerful enough for recursion, but there are also some things missing: ||||||||||||đệ quy||||||| Onze vereenvoudigde kleine set van vier grammaticaregels is krachtig genoeg voor recursie, maar er ontbreken ook enkele dingen:

adjectives like "big" or "purple", adverbs like "quickly", pronouns like "you" or "me".

Sadly, this video does not actually contain infinite recursive space, |||||||vô hạn|đệ quy|

but now that we're thinking like linguists, we can use our knowledge of language to continue to build up a more complete set of rules.

This is just the start!

But even with just four rules, we can see that sometimes completely different words have the same linguistic structure.

Other times, the same words have different linguistic structures.

We can see these similarities and differences by looking at language from the perspective of syntax.

Let's take these two sentences.

“Time flies like an arrow” means that the concept of time is fast, like an arrow is fast. ||||mũi tên||||||||||||| |passa|||flecha|||||||||||||

“Fruit flies like a banana” means that these small insects are fond of fruit. ||||a banana|||||small creatures||||

Both of these sentences have "flies" and "like" in them, but these words have different structural relationships with the rest of the sentence.

In this first tree, "flies" is the verb, and "like" is a preposition.

In this second tree, "flies" is part of the noun phrase and "like" is the verb.

We can represent that difference by drawing diagrams.

Don't stress about the triangles. ||||the shapes

Linguists use triangles within a tree to save space and represent constituents that are not the focus of what we're talking about. |||||||||||parts of a sentence||||||||||

But we can see how these shared words occupy different parts of each tree.

Or take the song about the mythical "One-eyed one-horn flying purple people eater". ||||||||||sừng|||| ||||||legendary||one-eyed||horned||||creature ||||||||||||roxa e voadora||

This could mean a song about a creature that eats any kind of people and has one eye, one horn, flies, and is purple. |||||||monster||||||||||||||||

Or it could be about a creature that eats one-eyed, one-horned, flying purple people. ||||||||||||with one horn|||

Or something in between.

Maybe a one-eyed, one-horn creature that eats flying purple people?

Some of these beasts are a lot more dangerous than others. |||creatures|||||||

Throughout this episode, we've been using rules and tree diagrams as a fairly simple way of representing the structure of sentences.

But there are lots of other ways of representing the same sentences.

There are many theories of syntax which have different ways of representing grammatical structures, each with their advantages and limitations. |||||||||||||||||||constraints or drawbacks

And there are some grammatical structures that syntacticians haven't even figured out how to represent yet! |||||||grammar experts||||||||

So far, we've seen sentences with absurd meanings but reasonable grammar. ||||||nonsensical||||

Next time on Crash Course Linguistics, we'll go deeper into meaning itself.

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