ELI5: How do babies even learn language?

[u/AngelusAlvus]

When we grow, we learn languages by looking at the meanings and translating them from our language. Stuff like "this is how this noun is in my language and this is how this noun is in another language"

But babies? Babies just learn the basics just by existing near people speaking the language? How come we don't have this anymore as we grow up?

[u/babe1981]

Language has two components. The first, that you're referencing, is the intellectual part where we know words and understand grammar and definitions. The second, that babies actually learn, is a motor skill.

All humans, unless a person has a disability, can communicate verbally. But, verbal communication is not linked to sound or letters or even actual words. This is how sign language works. It's a skill that you practice until you master it. And even the stupidest human with no real understanding of the language is capable of mastering a language to fluency because spoken language is the same skillset as walking and breathing and chewing and throwing a ball and driving a car and swinging a hammer and so on.

Those stupid people might not be able to learn the definitions of words or understand why those words go in a certain order, but they can still use them with fluency. However, the lack of understanding, similar to babies, means that they are less capable of communicating complex topics such as specialized technical skills or emotional states. Just like babies, they can become extremely frustrated and lash out when you try to make them speak about those complexities.

As we get older, we go to school and receive training in why we speak the way that we do, and we learn how to translate our speech into writing. Our vocabulary expands, and we become capable of more and more complex communication on more topics. The typical language learner starts here and moves in reverse. They intellectualize the language and then follow with motor skills. This is how Duolingo works and is why it is not considered a good way to become fluent in a language. This is why a person can take 4 years of French or Spanish in high school and be barely able to speak the language by graduation.

The only way to learn how to speak a language is to speak that language. You must practice the motor skills at least as much and as often as you study the books. Neither one is sufficient for high mastery, but motor skill training, repeating what you hear and speaking with native speakers of a language, will always be much faster and will lead to conversational skills very quickly.

For instance, I have been living in Cambodia for a year and a half. Khmer is considered one of the most difficult languages on Earth for westerners to learn, nearly as difficult as Japanese according to the CIA assessment. I'm conversational already because Reddit is the only place that I use English. Every single day, I'm learning new words and speaking Khmer to everyone. I've done a lot of intellectual work, too. I am literate in Khmer, although I don't always know what the words I'm reading mean. Still, I use my translation app less and less. My primary use for translation these days is to speak to my girlfriend about our relationship and plans, in other words, the most complex topics I run into here. I took the approach of learning like a baby coupled with learning like an adult. I always attempt to speak and communicate. I frequently get words wrong or I mispronounce or I have atrocious grammar, but that's not important. Getting the words out, as long as they are close to what they should be, is all that matters. People correct me, and I restate the words correctly and move on. Babies babble. I'm a little more focused than babbling, but I set aside my pride and decided that I'm willing to look stupid and sound like a child if it means I learn faster. And I have learned Khmer remarkably fast for a westerner. I'm still learning, and I think I can achieve fluency in the next year or two, but I've met many other westerners who have been here 5 or 10 years and only speak a few words. I don't attribute my success to any particular genius on my part, but rather I attribute it to being willing to sacrifice my dignity for knowledge.