Mind maps or brainstorms are probably one of my favorite techniques in language building (or idea generation). It is a free form way to let your ideas flow to the front of your mind and let the natural "domino" effet happen. One idea conjures another and soon you find that you have a nice vocabulary list. Most times students have at least one or two words they can associate to a given topic, so it also creates a context of success for participants.
Moreover, I believe it mirrors the way our brain really works. Being dyslexic, I know that I personally think in networks rather than in straight lines. But I have a hunch that we all think in a networked fashion and THEN organize thoughts more linearly. So mind maps echoes the way ideas travel and lets them come out before we need to organize or filter.
I use mind maps in two places. First I use them as a warm up or pre activity. In other words, before we get into a theme or topic, I will ask what words come to mind. I also use it as a comprehension check after a listening or reading activity. The interesting thing about using it as a comprehension tool is that, again, the participants can re-create the content without worrying too much about sequencing.
I have yet to find a student who doesn't like mind mapping. So I encourage you to take a look at the video of how I do it and leave me your comments if you have insights to share. Have fun!