This paper focuses on the relationship between the change of the mother tongue of ancient Hui Muslims and the appearance
of
the Xiaojing scripts. Scholars like Bai Shouyi and Chen Yuanlong believe that the basic language of Xiaojing is Chinese, meanwhile An Jiwu and other scholars connect the Xiaojing scripts with the Xinjiang dialect of Chinese used by local Hui Muslims and " the language of madrrasa". Based on the previous researches, the author suggests that the language of Xiaojing is the
Hui Chinese dialect. The paper discusses a special period-bilingual period, in the process of the formation of Chinese Hui Muslims, the Mongol-Yuan and early Ming period when two languages, both Chinese and Persian, were used. The earliest sample of the Hui Chinese dialect belongs to the early Ming period. The bilingual period ended in the mid of the Ming period when most of the Hui Muslim could no more speak and write Persian fluently and their mother tongue became Hui Chinese dialect. The appearance of the Xiaojing scripts should be after this time.