I would speak to your psychiatrist about it. Abilify and other antipsychotics don't usually cause speech defects. If its just cognitive confusion then that can happen and is not of concern. If it is tic like and does not come and go when you take the medication but occurs all the time and started suddenly that would be. But explain to your psychiatrist exactly what is, when and how it started and they can give you a better explanation as to what to do from there.
My 8-yo son has been on Abilify for a year now (for impulsivity and aggression related to his Asperger's diagnosis). He just started to "stutter" about 2 months ago, and we wonder whether it is related to ths Abilify. I can't find much online relating the two, though.