A few weeks ago, I spoke a little bit about some techniques used in infant language research. Someone had asked me to elaborate a bit more on how infants acquire language sounds. I thought the best way to begin this would be to talk about the order that these sounds are acquired before getting into the theories in later weeks.

The ability to acquire language is something that we as humans have innately. Whether it is spoken or signed, we can figure out grammatical rules without having to be explicitly told what they are. The methods that we use are somewhat of a mystery but looking at the typical development pattern of an infant, we can get more of an insight.

In the first six months of an infant’s life, their ability to produce language is essentially non-existent. They will make sounds and begin experiment with babbling as they approach 6 months, but there is not “language” being produced in the same way that adults produce language. What we do have evidence of is the perception of language in the first six months. As I mentioned a few weeks ago, we have evidence that infants can perceive the difference between similar sounds like “b” and “d”. In addition, we can use that same methodology to show that infants prefer the sound of human speech as opposed to non-human sounds.

Newborn infants have the ability to discriminate between almost any contrastive sound in any language, but by about the 6-month mark, their perception begins to narrow and focus on the language that they have been exposed to up to that point. To explain this a bit, let’s imagine a scenario.

In Hindi, one of the languages spoken in India, they have dental variants of the “t” and “d” sounds we use in English. These consonants are produced by making a “t” or a “d” sound with your tongue pressed against the back of your teeth as opposed to by your alveolar ridge. To get a better sense of this, check out this short video.

Now it important to know that in Hindi, these dental sounds are contrastive with the alveolar sound meaning that using a dental “t” instead of an alveolar “t” results in a completely different word being perceived. Think of it like how we make the distinction between the words “bog” and “dog” where the only thing that is changing between those two words is the place of articulation for the first consonant (this is called a minimal pair, and we will talk about them again someday).

The difference between dental “t” and alveolar “t” is likely quite subtle to your ears, and in rapid speech you likely wouldn’t be able to hear the difference. To a Hindi speaker, the contrast is quite clear, and they would be able to notice the difference in almost any situation.

Now to our hypothetical scenario. A newborn infant would be able to notice the difference and react to this subtle change in sound for the first few months of their life. By the time they reach 6 months of age, if they are growing up in an American English-speaking household in California, their ability to distinguish the two is likely completely gone. This is because they don’t need to know this difference. In standard American English, we do not make a contrastive difference between the dental and alveolar sounds like this, so there would be no need for an infant to focus on that feature. All of this is to show that even at such a young age, the infants language capabilities are being refined and fine-tuned to the language they are being exposed to.

Moving into the 6-8 month range is when we start to see the first signs of language production known as the babbling stage. During this stage, infants will start producing consonant vowel pairs like “ba” and “da” mostly in isolation at first. Around the 8-month mark is when they start doing what is known as canonical babbling. This canonical babbling is what we would think of as prototypical baby talk where they will produce repetitive sequences of the same consonant vowel pair (bababababa).

This is usually what we get up until the first year of age when the infant will begin producing single words to refer to objects (juice), actions (up), descriptive adjectives (hot) and social words (yes/no). They will not be crafting sentences at this point but will use single words to communicate the things that they want. If you have ever had children, I am sure you know just how early they acquire the word “NO” and their love for using it. This is the beginning of their process of linking the sounds that they are hearing and producing to meaningful content.

If at this point a child is producing what appears like a two-word phrase (“stop it” for instance), it is likely because they have memorized it as a single word. At this point, the only exposure they have to it is together in a phrase, so they have just memorized it as a chunk. This brings about a whole question of how infants are able to parse individual words based on what they are hearing (which I think is a whole post of its own so I will leave it for now. Trust me, it is very cool though!).

The majority of a child’s language in this one-word stage is monosyllabic and usually involves simpler sounds like “s”, “b” and “k”, but this is not to say that they cannot perceive more difficult contrasts. English speaking children are able to distinguish the difference between a “sh” and an “s” sound because it is an important distinction in their language, even if they cannot produce it themselves.

By around 2 years of age, infants have entered the two-word stage of language acquisition where they (you guessed it) will produce two-word utterances to communicate more complex ideas than they could with just one word. Their word learning rate at this point is quite high and they are learning roughly one word every two hours (provided they are being exposed to language of course. (As a side note, talk to your kids! It is important!!)).

At this point, even though they are using multiple words, they are still missing key markers in their speech such as tense or inflection markers. You won’t see them producing things like “I sat” at this point. They will most likely just default to the present tense “I sit” regardless to the time that they are trying to refer to.

And finally moving to the 2–3-year period of an infant’s life is when we see language truly explode! This is the telegraphic stage of language acquisition where they can string full utterances together, but they still aren’t quite using language to its full capabilities. If you have ever tried to have a conversation with a three-year-old, you probably notice that their speech is not perfect. They still tend to leave out functional words at this point like “is”, “do”, “at”, and so on. This gives their speech the telegraphic quality where we can certainly figure out what they mean, but it feels a little disjointed when you analyze it from afar.

Beyond the three-year period, we can see them start to develop their language further and start filling in these gaps gradually. So, this is the general pattern that we can observe in a typical child’s acquisition of language. As far as the theories of HOW this is working behind the scenes… well, unfortunately I got a bit carried away with this post so I will have to leave that for another week. The process doesn’t have a simple one sentence explanation and there is a lot of ground to cover on that topic alone. I would feel better about giving it its own space rather than trying to rush it here.

Speaking of the future though, now is when I break the bad news that I will be taking a brief hiatus from this blog until the new year. I have been really enjoying writing these posts, but unfortunately my studies are getting quite busy right now and I do not have the time or mental space to write posts that live up to my standards at the moment. Rather than churning out something I am not proud of, I think it is best to take a short break and start the new year fresh. Thank you to everyone who has been reading these week after week and I hope that you will all come back when I post again in the future. In the meantime, if there are any burning questions you have about linguistics, feel free to send me an email. Again, thank you so much for reading, you have no idea what your support means to me. I will see you all in 2022.