Dzongkha and Nepali are two most spoken languages of Bhutan. Dzongkha is the national language and is spoken in most parts of Bhutan. Nepali is spoken by people of southern Nepal, for most of them have their roots in Nepal. Assamese, Limbu, Santhali, Sherpa, Gurung, Western Gurung and Eastern Magar are other languages and dialects spoken in Bhutan.
Traditionally, public and private communications, religious materials, and official documents were written in chhokey (classical Tibetan script). A Bhutanese adaptive cursive script was developed for correspondence and now, like in past, chhokey only exists in written form and can be understood by few well educated Bhutanese. Dzongkha has developed since the 17th Century and is an offshoot of Tibetan language, but at the same time, it uses a different style of scripting. Meaning of Dzongkha is the language spoken by the dzong. Study of Dzongkha is compulsory in all schools of Bhutan, and English is used to teach subjects like mathematics, science and geography. Twenty-four dialects are listed in Bhutan and all these are living dialects.
Sharma, Rashmi. Bhutan and SAARC. New Delhi: Regal Publications, 2007.