I wanted a dialogue in Spanish in my current novel. A family is being terrorized by a drug lord and a stranger (Lincoln Steele) walks into the house with a gun after the wife walks in. The wife's husband says in Spanish, "Who is he?"
I ran that through a translator and it came up with "ΒΏQuien es el?" Thankfully I checked with someone on wattpad who previously helped me with another Spanish dialogue.
She said it sounded awkward and to write it as "ΒΏQuien es ese?" which is "Who is that?" And then she said to write it as "ΒΏY quien es ese?" (And who is that?) because Mexicans typically put "and" in front of the question.
I put the question out on wattpad and the two native Spanish speaking people who responded agreed with her.
The bottom line is, if you simply use a translator you're probably going to sound wrong. God knows what I actually said in Russian in my first Lincoln Steele novel.