At Kill Zone Blog: Rendering dialects and accents.
But what if you do want the character to have a heavy accent? Be clever about it. Give the reader an indication of the speech pattern the first time the character speaks, then use a few sprinkles of it every now and then as a reminder.
For instance, you can do a dialect-heavy first line and then pull it back in subsequent lines. Liz Curtis Higgs does this in Thorn in My Heart, a novel set in 18th century Scotland. A local shepherd greets a lost horseman with:
“D’ye ken whaur ye’re goin’, lad?”
You have to look that over a couple of times, but that’s what Higgs wants you to do. The heavy brogue is now implanted in our minds. After that she keeps the odd spellings to a minimum.
Good suggestion: start heavy, then go light.
Other good suggestions in the post.
Word choice is obviously another way of indicating accents without messing with the spelling — the post refers to that as well — or, in secondary world fantasy, with clarifying to the reader that different characters come from different cultures or different linguistic backgrounds, or both.
I was startled recently to discover that my brother, when he read my recent WIP (Tuyo, the obsessive one, if you’re curious), didn’t notice that the main protagonist never uses contractions no matter what language he’s speaking, or that no one uses contractions when speaking taksu. Only native speakers of darau use contractions, and only in their own language. Taksu obviously just does not include the option.
Word choices and sentence structure are also different for the two languages. I have faith that the reader will feel the difference, even if he or she doesn’t consciously notice them. That’s another way to handle linguistic variation, without having to mess around with spelling at all.