Is it something you routinely ask about, though, doclori? I don't think it would occur to me to mention it (yes, DS did this too) unless directly asked, and I had the impression from general (if population biased!) mother chat that it wasn't limited to HG+ kids.
I don't specifically ask about self-made languages. I do, however, ask about language in general, especially for kids who are under five years of age. For toddlers, I specifically ask how many/what words they say (mama/dada/up/hi/bye/more/etc). For toddlers, do they put 2 words/3 words/more together. For 3-5 year olds, who understands their speech and to what extent? Mothers usually understand most of what the kids say; by 4 speech should be mostly understandable to a stranger.
So although I don't ask specifically about that, certainly there's more than just a momentary discussion about language.
