How Do Children Acquire Language?
How First-Language Acquisition Works and What It Means for Learning English

Long before they can speak even a single word, babies are already hearing large amounts of speech. Different speakers have different pitch and vocal qualities, and their speed and pronunciation vary as well. Even so, every language has recurring sound patterns.

By listening to many speech samples, babies gradually learn those characteristics. In this way, they build the listening system that allows them to hear the sounds of that language. Here, we call this process speech perception formation. It is the foundation that lets a child hear Japanese as Japanese sounds and English as English sounds.

What matters is that babies are not memorizing each sound one by one from explanations. By hearing large amounts of speech and detecting the patterns that recur again and again, they gradually build the sound system of that language.

In writing, there are spaces between words, but in real spoken English, words are not pronounced one by one in neat isolation. Sounds connect, change, and sometimes disappear. For example, in I put it on the table., the sounds in put it on link across word boundaries and can sound almost like one blurred chunk. Even so, English speakers instantly find words within that continuous stream of speech.

Children do the same thing. By repeatedly hearing real spoken language, they begin to detect word-like chunks within the flow. This is speech segmentation. As they encounter the same chunk again and again, it is gradually stored as a word in the lexicon—the mental dictionary.

Even if a child can hear a word correctly, language is not usable unless its meaning is understood. So how is meaning acquired? Imagine a child hearing the word dog again and again in many different situations: a big dog, a small dog, a running dog, a sleeping dog. Over time, the shared meaning of “dog” across those different examples becomes clearer and clearer.

Each individual, concrete experience is called an exemplar. From many such experiences, a central image gradually forms—an internal sense of “this is roughly what a dog is.” This is called a prototype. In addition, dog is used together with other words such as bark, walk, and pet, so meaning grows as a connected network of words and experiences.

In a first language, meaning rises directly from the sound, so there is no need to hear “dog,” translate it into another word, and only then think about what it means. With enough similar experience, the same thing can happen in a second language: meaning can be understood directly from English itself.

The same is true of grammar. Children do not first learn to understand sentences only after being told, “English follows a subject + verb + object order.” Instead, they hear many sentences such as I want milk., I want this., and I want it. As this happens, they begin to sense a pattern: after I want, a word that names the desired thing often follows.

As experiences like these accumulate, what first existed as a fixed expression gradually expands into a form that can be used with other words as well. It develops from a formulaic expression to a phrase, then to a construction, and eventually into a larger grammatical system. Children do not memorize grammar rules first. They experience many sentences, notice what is similar across them, and build the rules of the language for themselves.

Grammar instruction explains English rules by using Japanese. When students are taught things like “this is the present perfect” or “for expresses duration,” they can understand and remember how the system works. This type of learning also plays an important role.

However, being able to explain English rules is not the same as understanding meaning the moment English is heard. When we listen to Japanese, we are not consciously thinking, “this is the subject, this is a particle, this is the past tense.” We simply understand and imagine the meaning as we listen. We can do that because we have already heard vast amounts of Japanese and encountered similar words and expressions again and again.

The same is true for English. It is not enough to know many explanations about English. Learners also need abundant exposure to English itself so that the patterns inside it can accumulate in the mind.

There is one major characteristic of the environment in which babies acquire Japanese: they are surrounded by large amounts of it every day. From the moment they wake up until they fall asleep, they hear the language their family speaks, and people talk directly to them as well. They encounter the same words and similar expressions again and again in slightly different situations. And this continues for years.

As a result, how they hear sounds, how they segment words, their vocabulary, their sense of meaning, and their grammar all develop together. This is why babies do not need a chart of phonemes, vocabulary lists, grammar study, or translation in order to acquire their first language. The vast amount of language built into daily life is itself the learning material.

In second-language acquisition, learners already have Japanese, so the conditions are not exactly the same as a baby acquiring a first language. The older learners get, the more likely they are to try to understand English by relying on Japanese sounds, Japanese word order, and Japanese ways of making meaning.

Even so, people who reach a high level of English share something important. Children who grew up in an English-speaking environment, returnees who attended local schools abroad, people who studied abroad and lived in English, and even learners with no overseas experience who had abundant exposure to English books and audio—all of them have built their English through rich experience with English itself, including the formation of English speech perception.

Through that experience, they become able to hear English sounds accurately, and then organize formulaic expressions, phrases, and sentence patterns into a system in the mind. When acquiring a second language as well, it is crucial to hear and read large amounts of English itself, and to build within oneself the recurring patterns that appear there again and again.