Unlike personal names (first name and surname), nicknames may vary from time to time and even from group to group depending on familiarity and relations between interlocutors or amongst group members. This paper examines use of nicknames in different communities of practice where members are well-acquainted enough to nickname each other based on personal names (internal variations) or personal features (external variations). The research is conducted in two universities in Taiwan: Tamkang University and National Taiwan University. Students who have constructed a community of practice are observed in their regular activities. Nicknaming practices are analysed and compared against Liao’s (2000, 2006) study of Taiwan-Chinese nicknaming patterns.In this study, the framework of community of practice is adopted in recruiting the subjects and addressing issues regarding gender. With this social theory, we are able to look at how nicknaming practices reveal identity issues of membership in a community of practice. From a sociolinguistic point of view, nicknaming represents a process of constructing individual identities within a group (Thornborrow 2004) and it is also the outcome of social interaction and learning. Membership of a community of practice is indexed by being able to recognise each other’s nicknames as well as other linguistic conventions. The results show that each community of practice has its own in-group knowledge that is exclusively understood by the members
