The final research, which is at the end of the third year (phase III) is expected to match model assessment “PLST” as well as the guidance in learning in kindergarten, which can be used by teachers to detect and monitor the development of language skills, identifying the amount of vocabulary and sentences are mastered children, and the stages of language development next. To achieve these objectives, the researcher adopted a model of research, development, and diffusion (Hopkins & Clark, 1976). Research phase of the study (first year), namely: a) preliminary study is intended to know the implementation of assessment in kindergarten groups A and B at district/city of Yogyakarta, b) the results of the research study are to find out the results of the research that has been done by experts in relation to the topic under study, c) analysis of the curriculum in intended to identify and map the development of kindergarten children language skills based competency standards and indicators of achievement. Stages are intended to capture the need assessment as a basis for designing a prototype model assessment “PLST”. And finally (first year), from all kindergarten which be the sample study, it was found that all kindergarten were using the general assessment without special assessment for development of children’s language, so it is necessary to create assessment “PLST” to detect the development of language skill for early childhood (kindergarten student). It has to continue in second to third year.