Although it is known that leaders can have a strong impact on whether employees voice work-related ideas or concerns, no research has investigated the impact of leader language on voice—particularly in professionally diverse contexts. Based on a social identity approach as well as on collectivistic leadership theories, we distinguish between implicit (i.e., First-Person Plural pronouns) and explicit (i.e., invitations and appreciations) inclusive leader language and test its effects on voice in multi-professional teams. We hypothesized that implicit inclusive leader language promotes voice especially among team members sharing the same professional group membership as the leader (in-group team members) while explicit inclusive leader language promotes voice especially among team members belonging to a different professional group (out-group team members). These hypotheses were tested in a field setting in which 126 health care professionals (i.e., nurses, resident and attending physicians), organized in 26 teams, managed medical emergencies. Behavioral coding and leader language analyses supported our hypotheses: Leaders' “WE”-references were more strongly related to residents' (in-group) and explicit invitations related more strongly to nurses' (out-group) voice behavior. We discuss how inclusive leader language promotes employee voice and explain why group membership functions as an important moderator in professionally diverse teams.