If you jump on a new language early enough and are proficient enough to be productive in it, you have a chance to actually land some jobs with it without having to take a pay cut. Letting people know and engaging in the community is a requirement though.

You'll meet other people passionate about it and ultimately network is everything ;)

Then again I end up with php jobs anyway because I enjoy sharing my knowledge (coaching, improving way of working, etc) but at the same time surround myself with people who I can learn from. (Be it business, architecture or a different language, all relative knowledge is valuable)