I would echo blackcat in noting that there is a very wide range of normal, both in the sense of broad population norms, and even among the GT population. My PG sib did not speak at all until age two, but then in full sentences (followed within weeks by spontaneously learning to read). One of my children has a same-age friend who began speaking at seven months, who experienced many of the same frustrations as your little one, but isn't currently necessarily performing as far ahead academically as some other later-developing talkers. (And there's nothing wrong with that, btw.)
Others will catch up in language over the next six months, at least in the sense of gaining verbal communication skills. (Perhaps not so much in actual vocabulary, though that may occur, as well.) This may ease some of the tensions.
One of the challenges, I think, is that there is a tendency for new parents to congregate in highly age-homogeneous groups (age of child, that is), with little perspective about the bigger picture of child development. When no one has any idea of what "normal" looks like, other than their N=1, and everyone is feeling the typical insecurity of the new parent, any (even slight) outlier touches a tender spot, which can result in disproportionate responses to natural variation.
For play dates, I think small mixed age groups would be my preference, where he can have interactions with developmental peers in various domains, though not all domains will match in the same individuals. Older siblings of age-peers are an excellent idea, especially as they are often more patient with toddlers than preschoolers who don't spend much time with younger children are (at least they are with toddlers who are not their siblings!). Especially if it's a play date with the age-peer and their older sibling together, which is a more natural grouping (i.e., less conspicuous), and more practical for the accompanying parent, anyway.
Don't forget to maintain your adult friendships that are not centered around having same-age children. That can be very important to your own mental health. (Which is the single best predictor of psychological health in children, after all.)
