If I understand correctly, the scores that reflect he is appropriately placed are the CogAT scores, not achievement scores. Struggling with letter sounds at age six, especially in a high-cognitive kiddo, is a bit out of the expected range, and does suggest that he might benefit, first, from some explicit instruction in phonemic awareness, and likely more comprehensive evaluation by a school, neuro, or clinical psychologist. If he is genuinely struggling with letter sounds, it is unlikely that it is due to feeling intimidated by his new peers.
Does the school teach phonemic awareness and phonics skills in their core curriculum? Do you see other areas of learning, attention, or behavior that seem "off"?
