@WBYeats,
Quote:Then can I say this?:
Simultaneous biliguals are children who learn more than one language from birth.
FROM BIRTH sounds like we need WHO HAVE LEARNED; do you think WHO LEARN is wrong?
Not wrong. I would say that both are roughly equivalent, but it would be more common to use "who have learned". They already have their speaking skills, and so "have learned" is appropriate.
But your example seems to be a definition:
Quote:Simultaneous biliguals are children who learn more than one language from birth.
In that case, I would say "who learn" is equally valid, and not grammatically wrong.