JennyC writes


I have a theory that children's mouths and facial muscles are trained into
certain positions while they learn the speak in whatever tongue they grow up
with. That's why it's so hard to learn to speak another language properly
when you are older.

I read somewhere that very young children apparently are able to hear a
whole range of sounds, but they become accustomed to those they hear
every day, and stop being able to hear the ones they don't usually hear
(in the sense that the brain no longer recognises them). So learning a
foreign language later is difficult because the brain has lost the
capacity to hear the sounds that aren't also part of the native
language.

One of my sons had a period of deafness while small. Although this was
corrected, and his results on tests showed him to be able to hear the
whole range of frequencies, the deafness seems to have coincided with
the critical period, and his speech and hearing was consistent with him
not being able to hear a whole range of sounds (basically all the
consonants), even though there was now nothing physically wrong with his
hearing.


--
Kay