cayer en

Asturian

Literally, “to fall on”.

(idiomatic) to realize
Nun cayí en que tabes en casa
I didn't realize you were home
(idiomatic) (used with a date, a month, a year...) to be then (a festivity, event...)
La navidá cai n'aviento
Christmas is in December

El cumpliaños la to hermana cai na selmana qu'entra
Your sister's birthday is next week