Abstract
This paper aims to describe the process of grammaticalization in Japanese potential expressions with reference to the situation in other languages. The following points will be illustrated: (a) As with other languages in the world, completives and spontaneous expressions are a source of potential expressions in Japanese. The multiplicity of forms of the latter origin is a characteristic of Japanese (§3). (b) Within potential expressions, the development of ABILITY>POSSIBILITY is observed cross-linguistically. In Japanese, however, the direction of change is the reverse: POSSIBILITY>ABILITY>MODALIZED ABILITY (§4). (c) Japanese potential expressions further come to express directives and epistemic possibility in some dialects, but the former is normally limited to prohibitive expressions and the latter type of change constitutes only marginal cases (§5). In sum, forms which originally denoted meanings other than ability and possibility have repeatedly come into use as potential expressions in Japanese, and have further changed their meanings within the realm of potential expressions. However they seldom change into other expressions with the exception of prohibitive. Japanese potential expressions normally give way to other forms which are grammaticalized in a similar fashion, and cease to be used as potential expressions.
