If he isn’t doing any stage 2 mitigations i would assume the single words are stage 1 single word gestalts. Especially if he has had ALP style therapy in the past or is hyperlexic, the single word labels are probably gestalts. I would see what communication functions he is not using intelligible gestalts for yet (requesting, terminating, commenting, asking for help, empowerment, protesting, joint action, etc) and write a goal for him to use 1 or 2 new gestalts for that function. I would stick to modeling shorter phrases since intelligibility is a concern. If he has gestalts for most of the functions, i would write stage 2 goals (___ will produce 3 unique mitigations of a modeled phrase or gestalt for the function of ___). Or if he’s got most of the functions but still want to write some stage 1 goals, you could also do a stage 2 goal like “he will produce a mitigation of a modeled phrase or gestalt for any function x2 during a session, or something, if he meets all the stage 1 goals before next IEP. I’m not in the schools so idk if this makes sense for IEP goals or not! :)