Abstract
In the lyrics of Japanese popular songs, double notation such as jikan(toki) and onna(hito) can be observed. Double notation is a form of notation that combines main-notation which indicates the written form, such as jikan, and sub-notation which indicates the phonetic form in the shape of notes or side notes attached to the main-notation, such as (toki). This study focuses on double notation such as jikan(toki) in which the main-notation and sub-notation do not have a corresponding relationship in the dictionary, and aims to clarify the diachronic changes of double notation in lyrics, by examining Japanese popular songs for approximately 50 years from 1969 to 2019.The results showed that the frequency of the use of double notation in lyrics can be divided into three periods: the 1960s and 1970s, when the use of double notation was stagnant; the 1980s and 1990s, when it fluctuated greatly; and the 2000s onward, when it became more stable. In addition, it was confirmed that the most frequent patterns of double notation in lyrics were those in which the part-of-speech composition was noun(noun), the word class composition was Kango(Wago), and the character composition was Kanji(Hiragana).
https://ror.org/04jqj7p05 
