Language codes are sent by the client, to the server, so that the server may return specific page information based upon this (such as translated pages). It seems though, that Google Analytics may not check for validity of these language codes before adding them to your charts.
For example, I have at least one language codes in the form *30789a483078979530789a5830789a2c307898a4
visible in my data.
Further analysis of the few of c
language-code visitors visible in the information from my website, it appears that they all originate from Linux OS (or undefined), and all use Safari or are part of a script getting data from a webpage (one in particular was http://pagepeeker.com )
Despite the language, the requests originate from all over the world.
In summary, I think it's just invalid data that's being sent to GA, and should probably be ignored.