Abstract
The subject of this paper will be the relationship between particularity in the beginnings of language learning in infancy and Zipf's law. Learning a language can be regarded as a process where an infant recognizes his/her own environment by words. The infant is in a transition from coarse-graining recognition of a known world to fine-graining one of an unknown world. This transution is irrational in terms of no necessity to step into unknown world from known world. Zipf's law is known as one of quantification expressing fractal structure and now-normal distribution, and a universal property of a phenomenon. In this study, however, the transition can be expressed a fixed point and quantified in term of Zipf's law obtained from a fixed point. On the other hand, in the plateau stage of learning a language, Zipf's law have not been observed, although it is said as a universal property of a phenomenon. The transition following the Ztpf's law suggests an appropriateness of the activity of the infant.
