Correção de frases: "I asked", "he asked'', etc

Which sentence is grammatically correct? Correct!

I asked what language speak the Bushmen.
He asked how the Bushmen did learn so much about animals.
They asked why the Bushmen were using Cyber Trackers.
He asked how works the Cyber Tracker.
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I asked which language the Bushmen speak/spoke.

(my tack on that one is, if I am talking right now and I am relaying the information to somebody else, I will say "speak''. If I am talking a past action, I say "spoke") Anyway, I am a learner just like you, so let´s wait for confirmation or correction.

He asked how the Cyber Tracker (whatever it means!) works/worked.
Avatar do usuário PPAULO 41375 6 32 726
What language would be understood as well, just that wich language is more usual/natural.