BEIJING, Jan. 18 (Xinhua) -- The Chinese Academy of Social Sciences (CASS) released a book on the 129 languages spoken by Chinese here on Friday.

    The book, "China's Languages," features 129 languages and gives an introduction to each in English, according to CASS.

    Sun Hongkai, chief editor of the seven-chapter book, said the content was based on an investigation of Chinese languages started in the 1950s.

    "During our investigation, we found some of the languages were already on the verge of extinction." He stressed "some were only used by senior citizens and have lost its communication ability".

    "We hope the book will be useful in protecting the culture of various ethnic groups and the harmonious existence of various cultures within the China boundary," he said.

    "Although China only has 56 official ethnic groups, some ethnic groups use two or more languages. This is the reason why we have collected so many languages."

    China is home to 56 ethnic groups. Han people, the largest group, make up about 92 percent of the country's population. The rest, the 55 ethnic minorities, share China's vast land and maintain their own traditions and customs.