first of all, the fact that you care about that person's mental comfort means a lot to them, very very nice of you. remember not to treat people with stutter like they are disabled, at least from my perspective, it makes me sad and then mad, and then actually encourages to keep going and fight on my own. what i would do is simply ask " hey, do you wanna be the one making the speech or the one creating the presentation. they will most likely want to do the presentation, not the speech. if they need to speak anyway, let that person choose the part of the presentation they wanna present, they will probably choose the shortest part.