“…This innovation has lasted over 400 years. The changes consist of two separate innovative processes: (i) ar-Deletion (for consonant-final verbs: Hibiya, 1999;Sato, 1977;Yamaguchi & Akimoto, 2001; for vowel-final verbs : Fukushima, 2004;Inoue, 1998;Ito & Mester, 2004;Kanda, 1964;Matsuda, 1993;Nakamura, 1953;Sano, 2010Sano, , 2011 and (ii) re-Insertion (Inoue & Yarimizu, 2002;Sano, 2010Sano, , 2011Shin, 2004;Shioda, 2000).…”