Does language determines mouth & throat evolution?

That depends on how closely the martian was looking.

Farfetched,

You're right it is a bit far fetched. Language evolves far faster than species. Language is flexible. I'd say mutations might affect language but things are not likely to do much in the way of going the other way around.

If someone has a slight genetically-caused mispronunciation it's not likely to have a great effect on their ability to reproduce. How many cases have you heard of where a person suffered an early death because of a lisp?

The effect you're talking about would be negligible if it exists at all.

I realised this years ago. Phisical features can define ´accent´. It is well studied by phonology.
Though anyone will speak any language with perfect accent, some accent strata are most likely to be achieved by some sorts of people, with some specific vocal apparatus.

Example: the so called ´english voice´. Also applied to the Portuguese.