The article raises three aspects of research on child speech: (1) defines the term 'child speech', (2) outlines the process of child speech development, (3) describes the research development of child speech. The aspects constitute three parts of the article. As far as the first aspect is concerned, the author claims that, although the term 'child speech' is understandable, it is ambiguous enough to be defined more precisely. The term has three meanings: (1) it indicates the period in a child life in which the child learns the language and verbal communication principle, (2) qualities of child language and communication, (3) child language research. Referring to the second aspect raised in the article, the author offers a new pattern of development phases of child speech, considering mainly the communicative criterion. Concerning the third aspect, synthetic characteristics of periods and trends in child speech research has been presented, beginning from the 19th century. In conclusion of the article which is a part of a larger paper, the autor indicates the complexity of schools and research trends in contemporary child speech studies.