I’m a little confused. Are we talking about a place that is not English speaking? I think you take some risk writing about a place you have never been, but I do think you can probably get quite a bit of help online. If you are writing a book you don’t need to worry about pronunciation, just spelling and usage. Like knowing people say The Bronx, not just Bronx, and that people who suburb NYC simply say, I went into the city, when talking about Manhattan. If you are writing in English for an American audience you only really need to know common usage in English. I think an editor can help you once you have the work done. Maybe I don’t fully understand the question though.