On a programming site, I noticed
a beautiful word use, "increasement."
Is there a term for, or how would you refer to, that - where you take a word, and use a different "form" of it.
So, you're making up a new "form" of a word which has never been seen before, but it makes sense based on variant "forms" of other words.
(This is sometimes done for humorous effect; and small children sometimes do it: in the example at hand it's just plain pretty.)
By the way notice I use "form" above ... perhaps it is not the best term (maybe there's another term, something like "tense" or ?)
Further - relatedly, it occurs to me that children learning language, particularly do this (often humorously to us adults). Surely, there's a term for this when children do it, since there's plenty of academic interest in such things.