"His shoes are small."
Translation:Liaj ŝuoj estas malgrandaj.
I put: "Liaj ŝuoj malgrandas."
Is that wrong? I thought you could do that with adjectives in Esperanto to convey, "it is [adjective]".
It's fine. I just put that myself, and it was accepted with no problems.
Esperanto doesn't have a plural form for verbs,^ only for nouns and their corresponding adjectives (and possessive pronouns). So when you convert an adjective into a verb, the pluralization gets dropped.
^Verbs are conjugated based only on tense, not quantity.
is: "Liaj sxuoj malgrandajs" okey, or is it "malgrandasj" or is it not allowed to make a plural-adjective a verb?