Facebook acquired speech recognition and translation startup Mobile Technologies, although it may be more of an acqui-hire than anything else.
Pittsburgh-based Mobile Technologies created Jibbigo, a speech recognition and translation app that could help Facebook connect uses of different languages -- although it already has a translation service, just not a voice-recognized one, according to TechCrunch. This could also be used for voice search.
Facebook will keep supporting the Jibbigo app, but likely not for eternity. It has things to do and services to integrate, after all. The Jibbigo app launched in 2009 and uses 25 different languages to decipher voice snippets or text.