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Babies have to learn a lot of language stuff before they can even say their first word. Exposure to language as infants doesn’t just help us say those first words but gives us the tools we need to acquire advanced language skills and learn more languages later on in life. In this episode of Crash Course Linguistics, we’ll learn about language acquisition and how the process differs for babies and adults.

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

What was your first word? Maybe it was ‘mama’ or ‘dada’ or some other family name, or ‘dog,’ or ‘ta’ for thank you.

I’ve been told my first word was dada, so I was a super original baby. Before a child says their first word, they’ve  already had to learn lots of other language stuff. Babies need fine motor skills to control their mouth and hands,   and their vocal tract isn’t even the right shape for making human speech when they’re tiny.

There’s also a lot that has to happen in the brain before first words. This is why it takes around a year for a baby to say their first word,   but you can leave your first lesson in a new language with half a dozen words. In this episode we’ll learn about language acquisition,   both when we’re young and as we get older. [THEME MUSIC].

Learning a language isn’t like learning that the Moon orbits the Earth, one fact, and you're done. Instead it’s many, many tasks across all of the levels of language:   phonology, morphology, syntax, semantics and so much more. There is a longstanding distinction in the research between the study of child language acquisition, and adult language acquisition.

Some linguists think these happen by entirely different processes,   and some think they are almost the same process with some tweaks. We'll learn about both! Let’s start in the womb.

By 30 weeks in the womb, you can feel physical sound waves through the amniotic fluid. It’s a bit like listening to the radio with your head underwater:   picking up the overall intonation rather than specific words. Shortly after birth, babies are more interested in language sounds than non-language sounds.

They also pay more attention to the voice of the person who gestated them   and people who speak the same language than to other voices and languages. Not long after that, babies with signed language around them pay more attention to signs. Babies are great at tuning into language.

Of course, we can't ask a baby, "hey, what do you think about these two words?" Instead, studies of infants make use of one simple fact: babies pay a bit more attention when they notice something new. We can tell if a baby is paying attention using a method called high-amplitude sucking. Babies suck faster on pacifiers when they're interested and slower when they're bored.

So if you give a baby a pacifier with a sensor in it, and then play "ba ba ba ba ba ba ba" over and over again, they'll eventually get bored and slow down. If you switch the audio from "ba ba ba ba" to "pa pa pa pa", the baby starts sucking faster again. That's how we know that they can hear a difference between those two sounds.

They’ve learned phonemes! Also, if a baby has typical hearing, they can distinguish between any two sounds that are relevant for any spoken language, up until around six to twelve months. Around that age, babies lose the ability to distinguish between sounds that aren't relevant for any languages they're exposed to,   which helps them pay attention only to the parts that are important.

After babies begin to figure out how their hands and mouths work, they start babbling. Babbling is what you might think of as classic baby talk: long, repetitive sequences of nonsense syllables. Babies who are exposed to signed languages, whether they're deaf or hearing children of deaf adults, also babble by making reduced versions of signs.

The cutesy way that older people address children is called child directed speech. In some cultures, child directed speech is very distinct from the kind directed at people one's own age. In other cultures, they are more similar.

But in both cases, kids learn language just fine! Kids generally say their first word or two around one year of age. There's a lot of variation in this age, though, and it also depends on how eager the adults are.

Easy syllables like mama, nana, baba, papa, dada, and tata are names for family members in many unrelated languages,   suggesting that a lot of people want their babies’ babbles to be meaningful. Even if you're more cautious, however, eventually toddlers are definitely in the one word phase. When a child systematically uses one word plus one gesture,   such as grabbing and saying “cookie” to indicate they want a cookie,   it means they’re almost into the two word phase, where they’ll say “want cookie.” These milestones might not get the spotlight on social media,   but they mark real progress in language acquisition.

Let’s visit the thought bubble to see some more language learning in action. Are you ready to do a linguistics experiment? Okay.

This is a wug. Now there is another one. There are two of them.

There are two…. If you said ‘wugs’, congratulations! You’re doing as well as a toddler acquiring English.

Before the wug test was introduced, many researchers hypothesized that children learn language by mimicking the people around them. And it's true that input is important. But wugs are imaginary creatures that children have never encountered before,   and yet they still know how to form the plural of them.

This shows that kids must have figured out generalizations, or rules, about how   language works, without ever being taught them rules that they can also apply to new words. The wug test was created in 1958 by Jean Berko Gleason,   along with a host of other imaginary creatures like luns, tors, and gutches. Kids can deduce for themselves how to fit all of them into a sentence,   just like you do when you learn or make up a new word.

Kids don't just absorb language verbatim from the older people around them,   the way you might download the full text of a dictionary onto your phone. We each figure it out, and reconstruct it as a system inside our heads. That’s how language changes each generation.

Thanks, Thought Bubble! Language acquisition doesn’t happen in a straight line of improvement. Children can learn a rule and then overextend it.

A very young child might say ‘went’, and then learn the rule that past tense is shown with the morpheme -ed, like with danced and jumped. Then the child might go from saying ‘went’ to ‘goed.’ It looks like they’re going backward, but they’ve actually learned a new rule! But in general, children follow a similar set of milestones within a range of ages, from paying attention and babbling all the way up to levels of double meaning, tact, and formal situations.

These milestones are why linguists often talk about a critical period when it comes to learning language for the first time. However, linguists are still debating about exactly how long the critical period lasts,   since we learn different parts of language at different times. Our ear for sounds is established pretty early, but complicated features like relative clauses take several years to learn, and we learn new words our whole lives!

Exposure to at least one language in infancy provides the foundation that lets you acquire more advanced language skills and additional languages later in life. Of course, it would be highly unethical to deliberately raise a child without language for research. But some unfortunate real life situations have given linguists insight into the critical period.

For instance, when deaf babies are raised with access to a signed language from a very young age,   they follow the same developmental stages as their hearing peers. From that solid foundation of a language they have complete access to,   they can learn further languages, including spoken or written language. But because of prejudice against deaf people, some deaf babies are raised without a signed language,   and taught only spoken language that they can't fully access.

Many don't start learning a signed language until later childhood, adolescence, or adulthood. And their earlier language deprivation results in cognitive difficulties for the remainder of their lives. But as long as children are exposed to an accessible language,   they do a great job with multiple languages.

In fact, there’s no cognitive limit to how many languages a child can learn during the critical period! So if a family lives in Malaysia and one of the parents also speaks Russian,   their child will easily learn both parents' languages. And if they move to Mexico when she’s in preschool, she’ll pick up Spanish, too.

The situation is more varied when it comes to learning additional languages at later ages. On the one hand, we can learn a second, third, or more languages by scaffolding off languages we already know, and our teachers can use our existing language to explain things. That's why you don’t see older language learners babbling for a year in Italian classes before figuring out that mom is “mamma”.

Plus, we’ve developed our fine-motor skills, and it's way faster to learn how to read in a new language if you've already learned in a language you know. On the other hand, the grammar of your existing languages can also influence your learning. If you’re an English speaker learning to say ‘purple rabbit’ in Italian,   you might have a tough time remembering that in Italian it’s ‘rabbit purple.’ When your existing language skills influence the learning process in a new language,   this is known as language transfer.

And babies are lucky--they just get to lie around all day and learn language and have other people take care of them! As we get older, we have other priorities. So, like with any skill, we're going to learn different amounts depending on how much time we spend practicing.

Luckily, there are some things that help adult language learners. The first is motivation to want to learn the language. The second is that it fits with your larger identity and goals.

You might really want to learn Japanese to watch your favorite anime,   but never make it through an exercise workbook. If your teacher gave you anime translation exercises,   your motivation and goals would line up and make you way more likely to finish the class. There are many different ways to learn language.

Learning one language at home and a second through formal schooling is a path that's over-represented in the research, but actually an anomaly, both in the world today and across human history. Instead, many people start learning another language in mid- to late- childhood or adolescence outside of formal schooling. People who learn and retain multiple languages are bi- or multilingual.

Some people use different languages in different domains, like at home versus at work,   or with friends versus in public. In fact, they might end up with domain-specific vocabulary words that they only know in one language. Maybe you’re multilingual but can only read one of the languages you speak, or maybe you grew up with a language that you understand but you can’t speak easily,   which is known as receptive bi- or multilingualism.

In contrast, other multilingual people might be around others with the same set of languages and constantly mix and move between them, which is a type of code-switching. Just as there are many languages in the world, there are many ways to be multilingual. One of those ways involves knowing a heritage language,   which is a broad term for any language that you have a family connection to that isn't also the dominant language of your current community.

It may be a language that you still know quite well, a language you have some knowledge of,   or an ancestral language that you haven't been connected with for several generations. Sometimes people lose touch with a heritage language because their parents were pressured,   implicitly or explicitly, to not speak it with them. But research has now shown that it's actually great for kids to grow up with several languages.

Regardless of how or at what age you do it, learning languages is a great way of understanding more about how language works and being able to connect with more people. See you next time, when we cover how languages change over time! Thanks for watching this episode of Crash Course Linguistics.

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