Well here's a fairly literal translation I found of the song. But I suspect there's a more singable set of words to the tune somewhere which Ernie's mother would have been singing.

Caro mio ben,
(My dear beloved,)
credimi almen,
(believe me at least,)
senza di te languisce il cor.
(without you my heart languishes.)
Il tuo fedel
(Your faithful one)
sospira ognor.
(always sighs; )
Cessa, crudel,
(cease, cruel one,)
tanto rigor!
(so much punishment!)