Have a field in which you select the language/s you speak; people speaking the same language can find each other more easily.
leads me to a different conclusion than this:
The original suggestion was for a field allowing people to state which languages they update in. Users are quite likely to enter languages they read in any such field: we need to think about how to handle this.
as it seems the OP was hoping to establish connections, not just with people who update in a particular language, but also speak a language.
Morphing it into a set of languages one updates is not necessarily a bad thing, but as others pointed out, languages spoken can definitely be an identity-level thing.
It might further aid the OP to have a way of setting what language a post is written in. This might be considered a future enhancement.
I like the idea of presenting the list as an unfolding set of checkboxes; keep it hidden at first, then unfold the more commonly used languages, then further expand to all languages; these should be clearly marked (emulating the cut tag feature would make for a consistent interface across the site).
In addition to the checkbox list, a write-in space should be allowed, as I can see people posting in conlangs, possibly (toki-pona springs to mind as something potential journalists might use). This might be a future enhancement as well.
spoken vs. updating languages
leads me to a different conclusion than this:
as it seems the OP was hoping to establish connections, not just with people who update in a particular language, but also speak a language.
Morphing it into a set of languages one updates is not necessarily a bad thing, but as others pointed out, languages spoken can definitely be an identity-level thing.