The form Moyō-da consists of the noun moyō ‘situation' and the copula da and expresses speaker's inference based on the evidence in modern Japanese. By examining the usage of the noun moyō diachronically, this paper reveals historical development of moyō-da, that is, the process how it has formed and established. Moyō-da began to be used in 1870-80s (the middle Meiji period), and was used continually after the 20th century. It is noteworthy that moyō-da was frequently used in newspaper articles. The article style became colloquial and the form moyō-ari declined in 1920s, therefore, the use of moyō at the end of sentence developed, and the form moyō-da established. However, moyō-da in 1920-30s was not equal to the one in modern Japanese from the viewpoint of a form prior to moyō. It seems that moyō-da became grammatical just like modern Japanese after the late of 20th century. This paper argues that moyō-da was formed and established as a result of nominality of moyō being declined. Furthermore, it turns out that the development of moyō-da is closely related to the property of writing style in newspaper articles.

In this paper we investigated the abbreviation patterns of loanword compounds in Japanese and the relationship between these patterns and the speaker's age.

Three types of abbreviation patterns exist among loanword compounds starting with a long vowel. In the first type, the initial long vowel tends to be maintained. The second type does not maintain the long vowel and replaces it with the next independent mora. In the third type, the long vowel is deleted in the abbreviation of the loanword compounds.

The current analysis obtained two results by the forced-choice test. First, it is shown that in existing examples of loanword compounds the initial long vowel tends to be maintained. Next, speakers aged 40 and older have a preference for quadrimoraic abbreviation patterns, whereas teenage speakers have a preference for trimoraic abbreviation patterns. This analysis reveals that there is a generation gap in the abbreviation pattern formation process, and that a new abbreviation strategy is developing among younger speakers.