Well, I *spoke* Thai pretty well when I was there as an exchange student at age 18, but it's been a long time and it's mostly dormant now. I hope I could relearn it, if I ever had an extended stay there and time to put my mind to it. Yes about the p/ph/b! When I was there, I just learned the sounds as I heard them, and only much more recently realized, oh, hey, I bet that sound was actually an unaspirated consonant! (Now that I've learned more about languages like Georgian, for example.)

Big sister-little sister cities! Oh, I love it. If one city refers to the other city, do they actually refer to it as "our little-sister city" or similar? If there's no word for "sister [age unspecified]," does that mean even something inanimate like a city has to be assigned an age ranking for the purposes of speech?