Ahh, the definition of eavesdropping. Going through effort to pick up on a conversation just out of earshot? Or forced to endure a conversation within your reasonable area of hearing? The first is obvious; don’t go through the effort. But your ears don’t have a shut-off switch for people next to you.
Which brings us to the next definition, entertaining. Why? Why on earth should it be MY responsibility to avoid hearing a conversation that triggers my interest? Obviously, the people doing the speaking aren’t worried about it, or they’d carry it on more discreetly. (Or they’re idiots, which is still their problem.)
But you mentioned it being spoken in a foreign language, which naturally piques your interest, on the very basis that it sounds different but you understand it. I’ve been exposed to several languages and can converse in a few of them. And if I encounter someone speaking near me in their own language, it’s pretty natural. Funny, but in US/Mexico border states, it seems that no white person should be able to understand Spanish, and they’re surprised when you know what they’re saying. I’ve not encountered such reactions with the Cubans in Miami or the Puerto Ricans in NYC. Although I have to admit, the Spanish used along the border is more difficult to understand, like the English used in downtown Detroit.