learn dutch

So today I went to have lunch outside on a picnic table outside of the building where I work. It's a nice sunny day, possibly the last one we'll see for a while. To my chagrin, there were no free tables. There was one table where two older gentlemen were eating and talking. I didn't recognize them, but I could have assumed the would be from our international division. I approached the table and asked: "Do you mind if I sit here?" They replied affirmatively, and as I sat down, one of them said: "As long as you don't mind if we speak Dutch." I said "Not at all, go ahead." So I opened up my newspaper and started eating and reading, and these guys went on conversing in Dutch. As I ate, I thought to myself- 'well that was nice of him to ask, and certainly unnecessary. i guess he thought i might feel uncomfortable if they sat there and spoke a different language. but i don't mind at all. but wait, that's a weird thing for them to assume. i wonder if he said that, not to make sure i didn't mind, but to make sure i didn't speak dutch, so that they could continue their private conversation without censoring themselves because i was there.' so suddenly i did not feel grateful, but more like a little paranoid. i started wondering what they were talking about. i started to wish that i knew how to speak dutch. then, i could pose as a provincial american, but effectively easedrop on dutch conversations... after a while they stood up and i said "have a nice day".