can simple present sentences mix with present continous?

[tweak]

Dear teachers,

I'm sorry I can't hear what you are saying because everybody is talking so loudly.

I'm sorry I can't hear what you are saying because everybody talks so loudly.

tweak

[Mister Micawber]

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Here, the second sentence does not work well, though it might be applicable to describe a recurring situation. When mixed, the continuous serves as the matrix (the ongoing activity) within which the simple is a (relatively) instantaneous act.
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_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mister Micawber