Derived from Sanskrit, Nepali is written in Devanagari script. Nepali is the official language and serves as lingua franca among Nepali of different ethnolinguistic groups. The regional languages Maithili, Awadhi, Bhojpuri and rarely Urdu of Nepali Muslims are spoken in the southern Madhesh region. Many Nepali in government and business speak Maithili as main language and English as their de facto lingua franca. Varieties of Tibetan are spoken in and north of the higher Himalaya where standard literary Tibetan is widely understood by those with religious education. Local dialects in the Terai and hills are mostly unwritten with efforts underway to develop systems for writing many in Devanagari or the Roman alphabet.