This paper considers how pattern languages can contribute to the formation of cognition and knowledge as well as the learning of experiential knowledge with Constructivist learning theories. According to constructivism, people do not simply absorb knowledge from the external world; rather, they construct knowledge through their experiences. Our present research endeavour intends to utilise the perspective of constructivism to clarify the definition of pattern language, how it functions, how it can be learned, and how it can support varied practices. This paper is the second of a series of research papers studying pattern languages through constructivist learning theories (Iba and Munakata, 2019; Iba and Burgoyne, 2019; Iba and Iwata, 2019) and it focuses on Lev Vygotsky's theories. In so doing, it overviews major aspects of Vygotsky's theories including "signs" and how they control behaviour, inner speech and the development of the senses, everyday and scientific concepts, and the zone of proximal development (ZPD). On the basis of these theories, the paper examines the manner in which a pattern language prompts actions, how it becomes sense when it is assimilated, how it associates with tacit knowledge, and how it supports development. The results of the undertaken investigation identify the functions of pattern languages in light of Vygotsky's theories as follows: (1) a pattern language functions as psychological instrument (sign); (2) it is a collection of words used to talk about experiences with others (external speech) and it helps to develop an individual's sense of the design/practice (inner speech); (3) as a systematic concept (scientific concepts), a pattern language reconstructs implicit spontaneous practical knowledge (everyday concepts) for the design/practice; and (4) a pattern language works as a medium that supports development in the ZPD.