Abstract：Children acquire language in interactions, and all groups with whom children interact may influence their language development, including kindergarten teachers who need to create a positive language environment. The language used by kindergarten teachers for instruction is referred to as Child-Directed Speech (CDS). This study collects kindergarten teaching videos from Bilibili and audio recordings. It examines the longitudinal dynamics of kindergarten teachers’ CDS along four dimensions: phonology (such as pitch and speech rate), vocabulary (including interrogative sentence final particles, epistemic modality, and pronouns), syntax (such as the mean length of utterances), and pragmatic strategies (question types). The study reveals deficiencies in the developmentality and proposes several strategies for improvement, such as increasing the average speech rate, lowering the mean pitch, increasing syntactic complexity, and using more open-ended questions in the second semester of senior-class children. Improving the developmentality of kindergarten teachers’ CDS can organically integrate language preparation into the kindergarten curriculum and facilitate a scientific transition from kindergartens to primary schools.
