> Worth keeping in mind that Helen Keller didn't loose her hearing (and sight) until an illness at 19 months old.
While this is in fact an important sample, this doesn't imply much about how humans develop after 19 months, much less how they develop before 19 months.
> At this age, a child's brain has already locked in the sounds for their native language and lost the ability to learn non-native sounds (hell, research suggests that unborn infants can recognise the difference between their mothers native language and foreign languages before they even leave the womb).
We have nearly zero clue how the child's brain recognizes their "native language". We know they react differently at different stages of their development to the same stimulus, which is occasionally linguistic. We have nearly zero clue what the mechanism is that corresponds input to measurable output. This is a very disingenuous characterization of the data.
It's also worth mentioning that the root of this question is trivially false—people obviously learn language after the age of five. Such haphazard presentation (at best) should not be taken seriously.
While this is in fact an important sample, this doesn't imply much about how humans develop after 19 months, much less how they develop before 19 months.
> At this age, a child's brain has already locked in the sounds for their native language and lost the ability to learn non-native sounds (hell, research suggests that unborn infants can recognise the difference between their mothers native language and foreign languages before they even leave the womb).
We have nearly zero clue how the child's brain recognizes their "native language". We know they react differently at different stages of their development to the same stimulus, which is occasionally linguistic. We have nearly zero clue what the mechanism is that corresponds input to measurable output. This is a very disingenuous characterization of the data.
It's also worth mentioning that the root of this question is trivially false—people obviously learn language after the age of five. Such haphazard presentation (at best) should not be taken seriously.