Two negative suffixes in central Kansai dialects, -n and -hen, recently exhibit similar usage, especially in the young age group. Results of a survey in Osaka and Nara show that young speakers prefer -yan, a new negative suffix found for such verb conjugation types as two-mora vowel verbs and irregular conjugation verbs. This paper reports the diffusion from Wakayama and Mie to Osaka and Nara through geolinguistic surveys and other relevant studies. The paper argues that motivations of the linguistic change from -hen to -n are internally determined by the loss of the semantic distinction between the suffixes, and externally determined by the re-organization of the negation system and the practicality of these suffixes. Other non-consonant, two-mora verbs have not demonstrated changes from -hen to -n directly. Instead a new suffix -miyan, as in miyahen ('not' see), was adopted in the process of change. This -miyan is not observed in standard Japanese. This hypothesis regarding the change of these negative suffixes is derived from the model of the linguistic change of a Japanese-based creole in Taiwan.