That's just my impression from browsing through Leabhar Mór Bhriathra na Gaeilge, at least. Also, Ulster uses synthetic forms for muid in the Conditional, according to that (Connacht doesn't) where as Connacht uses it for siad (whereas Ulster doesn't)
The answer it gave me was leas but I have never seen that word before and it is not listed as an alternate when you hover over I or read. Why does Duolingo pop up words that you have not seen previously. BTW, this was in the strengthening exercise, not a lesson.
It's like Spanish, where the pronoun is subsumed into the verb. léim = léann mé
So is it just the first person (leim, leimid) that has a special conjugation, and everything else is leann [whoever]?
léim is a noun meaning "a jump" or "a leap", and it's also a verb meaning "jump" or "leap".
But the Irish for the verb "read" is léigh, and in the present tense that becomes léann ..., and the first person singular uses the synthetic form léim:
léim - "I read"
léann tú - "You read"
léann sé - "He reads"
léann sí - "She reads"
léimid - "We read"
léann sibh - "You read"
léann siad - "They read"
léim mé - "I jumped" (past tense)
léim tú - "You jumped" (past tense)
léimim - "I jump" (present tense)
léimeann tú - "You jump" (present tense)