This study presents a comprehensive analysis of the functions of the Japanese sentence-final particles ne and na, by examining both their resemblances and contrasts, and elucidates some facets of the identity-language interface. It asserts that the use of na does not directly adverts to speaker biographical features. Rather, its special tune of ‘friendliness’ is tightly related to sociocultural values on gender and formality in the Japanese language, and thus its usage displays the speakers' specific gender, age and social status.