Each language differs in pronunciation, grammar, and intonation from one another. Mongolian sounds are pretty different from other languages in that they require the flexibility and muscle development of speech organs. This study aimed to identify the characteristics of children's pronunciation in phonetic and phonemic acquisition to identify how differences in pronunciation vary from child to child and pronunciation changes. Utilizing interviews with each child saying a single sound and word saying task, we randomly selected 1083 children q1aged 2to 5-year-olds. As a result, we have found: a) early childhood sound pronunciation status whose mother tongue is Mongolian; b) at first, children pronounce sounds clearly which involve organs in front of the speech organ, and the speech sounds that are pronounced in the middle and behind places of speech organs become more apparent later c) the most challenging speech sounds for young children are [r], [s],[ts], [sh], [dz], [dj] and [ch]; d) the Aprocess of changes of pronunciation changes differs in each child and has 2-3 stages. Today, there are no significant studies on early childhood sound pronunciation skills. We assume that policymakers and early childhood educators should periodically investigate this study.