Is a (non medical) specialist also a "doctor"? Is a historian and a scientist a "doctor" in their field? Or would you call them a "specialist"? I have 3 characters, one is a linguist and the other one is sort of a historian. The other is a scientist. Would i use "Dr." for all 3 or is there some other term i am missing that i should use? Also, the characters are in the military, if that helps...
They would be addressed as "Dr.," yes, as long as they possess a doctoral degree in whatever subject it is, but it wouldn't be that they are a doctor of linguistics, it would be that they are a doctor of philosophy in linguistics. I believe that there is an exception for law and theology: people with an equivalent degree in those fields could be referred to as "doctors of law" and "doctors of theology."