Thanks for the link. I hadn't actually considered language learning in an ROI-fashion, but it's obviously something I should think about before making heavy investments.

I still think it worth the time since my field involves dealing with non-English parties often. Though I have no distinct need for bilingualism at the moment, it will make me more hireable. However, I do need to evaluate my time learning Spanish against, say, the gains of spending that same time learning programming languages.