so wry duolingo. i see you.
about nhà lãnh đạo...does this refer to any leader, e.g. business, familial, etc, or only government leaders?
Normally government heads and leaders in a particular field of study/profession.
Speak slower please.
what a strange sentence...apropos of nothing!
Is "the" necessary?
Yes as omitting it would change it to "leaders" (indefinite).
Vietnamese does not need articles.
Can I just say "các lãnh đạo" instead?
Các lãnh đạo is plural. Lãnh đạo means leader. Các lãnh đạo means leaders