It is a kind of collection gathered a total of 25 in-depth writings of Vietnam Institute for Lexicography & Encyclopedia's research staff that were written from the year of 2000 up to now. The writings covered the four groups of essential issues of the language ( both spoken & written ) of Vietnam ethnic minorities ( EM ): 1 - Phonology. Dialects. Written language. 2 - History of development. Comparison. 3 - Gramar. 4 - Language & society. Here are some the most prominent ones: 1 - Phonetic system of the language of the Cuoi; of the Cotu; of the Khang; of the Cadong; of the Cham Hroi; of the Raglai ethnic minorities. 2 - Thinking about the Project of reforming a written language of the Cotu EM. 3 - The tune ( tonality ) & origin of the tune of the in language of Cho Lao EM. 4 - The tune & the Cham substratum in the Cao Lao Ha ( Bo Trach District, Quang Binh Province ). 5 - The issue of phonetic scale / register of the Mnong Preh EM language. 6 - The issue of dictation of the ethnic minorities that belonged to the Chinese - Tibetan group. 7 - Some about origins of the Viet ( Kinh ) & Cotu languages - a view from lexical materials' angle. 8 - The issue of the Tho ethnic group - a view from language's angle. 9 - The people of Ngan and some thinking about the issue of determination of ethnic constituent. 10 - The parts of speech in the Bahnar EM language. 11 - The manners / ways of address of the Tay; the Ede; the Hre ethnic minorities. 12 - The languages in education for mountainous ethnic minorities in Vietnam.