[Excerpt] In global firms multinational teams (MTs) are a way of life. Increasingly these firms find it essential to assemble just the right mix of talent from around the globe to tackle complex tasks.Typically MTs perform much if not all of their work using a common language which, while necessary, can have its drawbacks. For example, it is unlikely that all team members will be equally proficient in the chosen language. This can cause problems for team members who are less facile with the language and, thus, find it difficult to contribute to the work of their teams in a timely and meaningful way. These personal challenges, in turn, can accrue to the team level. A few recent studies suggest, for example, that asymmetries in language proficiency in MTs undermine trust and confidence among team members and often lead to the formation of cliques and uneven levels of influence that hamper team processes and eventually undermine team performance. Overall, though, little is known about the ways in which language proficiency affects those who work in MTs or the ways in which variations in language proficiency within teams affect their ultimate performance. The present study was designed to shed light on these issues