Is a character with a stutter annoying?

In a recent work I have a pair of near identical twins, Samuel and Ryan, Sam, the older twin, has brown eyes while Ryan, the younger twin, has hazel eyes. Ryan also has a stutter. He stutters his way through the story, which involves him having to replace his brother, the assistant CEO of a major company, after he disappears. What I'm wondering is, could this become annoying to readers? It's vital to the story, as its one of the many differences between them and makes it difficult for Ryan to disguise himself as Sam.

It could potentially be, if you decide to break apart every line into a mess of dashes and breaks. But put it in the narration and it's easier to do. Patrick O'Brian does this well with Padeen Colman, an Irishman with a cleft palate, a stutter, and a very limited knowledge of English; it's described in the narration that Padeen's speech is often broken and nearly incomprehensible, but not in a way that annoys the reader or breaks the flow.

I've described it in the narrative, but I also break up his speech when his stuttering is most prominent. The most of the time, I don't put it into his speech but the readers are reminded of it by the occasional character telling him to stop it.

I'd treat it like an accent. You can occasionally put it in the dialogue, but it's best to just mention it in the narrative. The readers mind can supply the actual stutter and you won't have to worry about irritating people.

Yup. As always it's down to execution, but you've got the idea down.

So I just occasionally add it in when appropriate, right?

I'm suggest putting the stutter in the text, but being very light with it. A little goes a long. If the character stutters once per paragraph it's plenty; people will get the point (Although, naturally, you can have him stutter a lot every once in a while to show that he's stressed or flustered).

This. Also, watching a character fight not to stutter can be surprisingly dramatic in the appropriate circumstances.

Right. I see where I could derive drama from Ryan's stuttering. I have a scene where a group of guys attempt to mug him in a crowded shopping centre, and I'm not sure whether to cut down on his terrified stuttering or to emphasise it.

Only emphasise it where it is a plot point or adds to the story, otherwise narrate it.

Ah, thanks.

Depends on how you do it. If you have the character stutter every line? Hell yeah. Break it up, and maybe realize that they won't stutter every word. Sometimes a stutter is conditional.

Tim Stryke, my character who has a stutter usually stutters with his classmates, kids who usually tease him, or adults who scare him. He stutters because he gets anxious or he has a hard time verbalizing what's in his head. Sometimes he'll start stuttering when he's getting frustrated trying to say something.

I can just suggest considering why your character stutters, and then think about the conditions.

It might be best not to make the character stutter with every word. I remember the dubbed version of Ominas Crowe had him stuttering one or two words with ever speech bubble. Not enough to be annoying and still helps separate him from other characters.

He stutters most on the letter 'R' and the letter 'S', so he introduces himself as 'R-Ryan Evans' and calls his brother 'S-Sam'.

I've got something else to bring up.

In another work of mine, there's a character who repeats the first two letters of most words. Since its from a viewpoint of someone who particularly dislikes this character and finds this annoying, should I try to make it annoying for the reader too or should I not?