When I was preparing to come to Kenya in 2007 I bought a pocket guide to learn Swahili. I wasn’t too serious about practicing, but I do remember sitting on the beach a few times reading that book (I even made flash cards). I’ve gotten pretty good at Swahili over the last few years so I guess it wasn’t a complete waste of time, but there are a lot of phrases you learn when you’re first exposed to Swahili that aren’t really used much by Kenyans themselves.