We’ve talked about them a couple times before (more than a couple times, in fact) but I’d like to leave something very clear:
You are free to write your character’s accent as much as you want, however, people are also free not to read your story; harsh truth, but truth nonetheless.
I more than agree that if your character has a particular way to express themselves, you can point it out through dialogue. I encourage it. Whether it is that, like, they use verbal crutches and stuff (they’re perfectly fine) or they use a very formal syntax and grandiloquent word choice (your character may be a bit pretentious), it shows something about their character, which is always useful specially if you want to back up certain statements (with the pretentious person, for example that they are suave, or wannabe suave depending on the context; on the other hand abrupt sentence structure may reference the character’s preference for straightforwardness, only looking to talk as much as it is necessary to do so).
Finally, accents in my opinion are a particular layer of your characters’ speech that should be used in moderation. It has the chance to be very, very annoying, and/or very, very offensive (particularly quite racist or classist), and sometimes only saying your character has a French accent may give us the feeling that they are talking in a French accent.
You are reading this right now in Morgan Freeman’s voice.
(warning: gif / gif not mine)
Sometimes dialect may make an entrance (dialect is different from just accents because dialect involves vocabulary and grammar; accent is pronunciation), which’s okay, y’know, so long as y’don’t exaggerate.Because if you overdo it (the way someone may overdo a character that stutters), it’ll disrupt the flow of my reading because I’ll be too busy trying to understand what you even mean.
There’s also a special kind of issue with characters whose first language is not English. If it’s shown your character speaks perfect English, has done so for a while, and then drops the occasional little Spanish word in every other sentence, only that point out that sí, they speak Español, then that’s not only a bit extraño (if they speak perfect English, why would they do this?) but offensive (because we know the answer, that’s why).
See gratuitous Spanish, German, and French (among others).
This only applies if it’s not quite explained why they do this. If they’re not perfect English speakers, or if they are doing this deliberately for any other reason, then you may not be doing this. However, sometimes not even people that are not fluent in English will speak this way. More often than not, they’ll try to express themselves as clearly as possible with what they know, and if they don’t know how to say something, they’ll try to explain it. Gratuitous (insert language) is just there to remind the readers these people are foreign and different, and that’s just not acceptable.
See my accents, character’s speech, and dialogue tags for more on this.