A vocabulary is used as one of the indexes of the language development, and it is pmportant meaning to grasping vocabulary development. But, there is a little research that a vocabulary in the 12-23 Month wa investigated. The purpose of this study is to investigate the vocabulary of the child in the 12-23 Month. We analyzed it about the number of average vocabularies, the part of speech atructure, the different in sex. The results is following there were two stages in the vocabulary development as that result. There were many nouns. And it was the result that preceding research was supported with a part of speech. A noun could be thought to occupy an important position in the early vocabulary development. It guessed the matter that it increased after a 24 month. A difference in sex became clearer than 22month. From now on, the vocabulary which becomes the index of the development evaluation, and the number of vocabularies will be examined.