This study considers the mechanism underlying how people use unique patterns of language use as a greeting message, using Konnichiwa( : good afternoon), and Konbanwa ( : good evening), a simple and common message appearing in Japanese mobile phone e-mail (Keitai-mail), as an example. The data corpus analyzed for this study consists of 43,295 mails for communication purposes from 60 Japanese young people. The result shows that people apply uniqueness in a limited way, and moreover their unique use of language is largely affected by the standard rules of Japanese, including sound information such that as (ha) is pronounced /wa/ (wa).