Translation:Who trains these children?
That first מ from מאמן sounds like a נ
is "who coaches" an acceptable translation?
I would say האלה...
What is the difference?
Why is "אמן" (artist, Amen) in the word "מאמן" (train)?
Well, the "artist" אֳמָן is the odd man out, which is an Akkanian-Sumerian loanword, but both אָמֵן and אִמֵּן come from the same root אמן "to be firm, trustworthy".
When do we use האלו rather than האלה ?
Well, אֵ֫לֶּה and אֵ֫לּוּ are used the same. Both are plural in both genders. So הַילָדִים הָאֵ֫לֶּה would be correct too.
I really hear "mina" on מי. Do where is the "נ"?
I suppose you hear the nasal consonant of the next word מְאַמֵּן.