Cross-cultural communication has become increasingly prevalent in organizations and education systems. Such communication often takes place in a distributed fashion, and many studies have examined the impact of computer-mediated communication (CMC) on distributed cross-cultural groups. For example the literature points to cultural factors that could cause communication failures, such as individualism vs. collectivism, high context vs. low context, and power distance. We contend that language proficiency, a basic and fundamental difference between people from English speaking countries and other countries, is often neglected by researchers. Therefore, we have begun a detailed investigation of cross-cultural group chat. We chose text chat as a target technology because previous studies reported it as non-native speakers' preferred choice for CMC. Our study revealed that language proficiency played a pivotal role in cross-cultural group chat. When people conversed at different levels of proficiency, turn taking was severely disrupted, causing confusion and neglect of discussion points. We also found that some native speakers hold back ideas to accommodate the non-fluency of non-native speakers, slowing down the group process and outcomes. Working from these findings, we discuss possible designs that could assist both non-native and native speakers in cross-cultural group chat.