Purpose: Our purpose is to study how language proficiency and cross-cultural adaptation affect ethnically diverse teams in their cross-cultural communication competence. Methodology: The data was collected through six interviews of team members working in a product development project in a multinational company. The interviews were conducted in March of 2012. The data analysis followed an interpretative thematic analysis inspired by Boyatzis (1998). To analyze the data we have utilized some steps of the thematic analysis. With the analysis it was identified that ethnically diverse teams build language proficiency and cross-cultural adaptation. Findings: The findings from this research indicate that cross-cultural adaptation and language proficiency should be considered as important dimensions of cross-cultural communication competence within ethnically diverse teams. Language proficiency remains a challenge for many ethnically diverse teams and should be included in studies related to communication. Employees’ ability to adapt to the current environment and culture has an essential impact on team communication. Research limitations/implications: The research was done in a Multinational company based in Sweden within one team at Electrolux AB, therefore implications from our study may not be applicable to all ethnically diverse teams in Multinational companies globally.