In a book we are reading there is a sentence that goes "What makes his face so strange?" As non-native speakers we are wondering if there is any difference in meaning if you say "Why is his face so strange?"
This "What makes..." sentence is a translation from the Japanese and we are trying to understand the nuance of this translation.
Thank you.
"What makes his face so strange" literally means "What force or mechanism causes that strange appearance of his face". This is pretty much the same as saying "Why is his face so strange" -- there is not an obvious "subtle" difference in the meaning of the two.
Note that in either case the question might be rhetorical/sarcastic, and if not would usually be inquiring as to what thought or mental process might be producing the observed expression on his face, vs asking if there is some physical cause for his appearance. (Though, obviously if his face is black and blue with a bandage over one eye the question would likely be asking for a physical cause.)
What makes
is asking what thing, condition or feature that is present
Why is
is asking for a reason, cause or condition behind the observation
Both serve the same general meaning, as both are not asking for an accurate or specific explanation. Answers are probably not going to reflect the specific meaning of that difference: so it is probably idiomatic.
Also, people will often ask "why?" when a real explanation is not going to be given, as in
Why do you always do that?
The answer is not usually going to be an accurate analysis, it more commonly would be answered with an excuse or rationalisation.
