The Interim Transitional National Council of Libya has a website up now, at which you can watch representatives of various towns declare their allegiance to the revolution and/or transitional government (and, in at least two cases, explicitly say they don't want foreign intervention.) These statements, as one might expect given the official context, are essentially in Standard Arabic with few dialectal features (although the numbers tend to be pronounced fairly dialectally.) But the first statement, from Nalut in the Nafusa mountains of the west, has a surprise at the end: it turns out to be bilingual, with a Nafusi Berber summary given at the end (from 1:29 on), opening with Azul fellaken Ilibiyen, "Greetings, Libyans." A nicely-balanced gesture, that - strongly reaffirming national unity by pledging allegiance to a government that currently isn't even geographically contiguous with it, while also implicitly saying, in the face of years of Qaddafi's nonsense: we have our own language as well as Arabic, and we think it's appropriate for addressing the nation, not just for talking to each other. That balance - neither suppression of minority identities for the sake of unity, nor self-absorbed pursuit of minority rights while ignoring oppression affecting the whole country - strikes me as a good omen for Libya's future, if only they manage to end this war fast enough.
A very large majority of Libyans have Arabic as their mother tongue - in fact, Western Eastern Libya was described by the colonial anthropologist Evans-Pritchard as the most Arab place on earth outside Arabia itself. However, the country also has a noteworthy Berber-speaking minority (about 5%, if you dare to trust Ethnologue; it's not as though anyone's ever counted them in the past several decades.) Most speakers are concentrated in the northwest, where they (traditionally, for once) call themselves Imazighen: the port of Zuwara, along with many towns of the Nafusa mountains, such as Yefren and Nalut. All of that region - Arabic-speaking towns as well as Berber-speaking ones - is currently reported to be free of Qaddafi; language, thankfully, does not appear to be acting as a dividing factor there. A quite distinctive Berber language is spoken in the desert oasis of Ghadames on the Algerian border. There is a Tuareg community in the southwest, around Ghat and Ubari. The isolated Berber-speaking communities of Awjila in the southeast and Sokna near the middle are shifting to Arabic (this process is almost complete in Sokna) - their languages are of extreme historical interest and are very inadequately documented. Other longstanding linguistic minorities (the Muslim Greeks of Sosa, the Teda of the far south, etc.) are much smaller, numbering in perhaps thousands each. But for decades, Libya has been practically terra incognita for descriptive linguistic research: even work on its Arabic dialects has been scarce, let alone on politically sensitive minority languages. When (inshallah) the Libyans establish a stable and free state, it would be well worth documenting its linguistic diversity, both for better interpreting North African history and for informing Libyan educational policy.