TOL:-
When I was growing up, the emphasis is on "Communication".
You dont have to be a Philosopher or award-winning Writer, but you must be able to have basic Communication skills eg. being able to ask for direction, being able to give direction etc.
If you ask me, I would say teach your kids Hokkien, Cantonese, Malay, Hindi, Tamil, English etc.
It would be so great if your kids can speak a few languages and dialects, rather than just be Bilingual only.
Anyway, what is your "mother tongue" ?

Does your mother speak Mandarin to you ? Or English, Hokkien, Teochew, Cantonese etc ?
If your mother does not speak Mandarin to you so why is it called "mother tongue" ?

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Ha Ha ... language, will always bring out the strong feelings in most people so I will leave my comments as it is before I start having a strong debate on this issue.
And I'm not interested in having a debate on something I cant invest in.

It's all about "how much you made when you were right" & "how little you lost when you were wrong"