Two words for "sorry" that aren't interchangeable

Perdona / Perdone

per-DOH-nah / per-DOH-neh — Excuse me / sorry

"Perdona, ¿sabes dónde está la parada de metro?"
Excuse me, do you know where the metro stop is?

"Perdona" is for someone you'd address as "tú" (a peer, a stranger your age or younger); "perdone" is the polite "usted" form, for someone older or in a formal setting. Mixing them up isn't a disaster, but native speakers will notice.

"My own abuela would still correct me if I used "perdona" with her instead of "perdone" — some habits from childhood never really leave you."— Graciela