I stutter and I’m in grad school right now to be an SLP. It is typical for kids to go through periods of stuttering, however I’d have to hear him or if you had an example I could tell if it’s typical vs. atypical disfluencies. Most of us who have developmental stuttering (won’t go away)start before we are 4-5. If he continues to stutter for 6 months then I would get him assessed for sure.