So I just got a call on my cell. I didn't recognize the number, so I let it go, and the person, not surprisingly, didn't leave a message. They did follow up with a text, however, which makes it clear that they didn't listen to my outgoing message—I would imagine they hung up once it got kicked to voicemail.

I'm thinking I should reply, saying that they had the wrong number, just to be polite. However, the message was in Spanish—which I don't speak—so I have no idea what they actually said (not that it's any of my business what they're saying to the intended recipient), so if I do reply, what does one say in these matters? And should I say it in English or Spanish?