Cross-cultural group chat is an important option for supporting communication in both industry and education settings. However, studies of such interactions have reported persistent communication problems that appear to be due to mismatches in non-native and native speakers' language proficiency. With this problem in mind, we have been exploring a conceptual design called Instant Annotation. Our design concept supports a kind of threading in chat using annotation, thus offering para-communication support in cross-cultural group chat. As part of this design investigation, we studied native and non-native speakers in a group chat activity, shared the new design concept, and interviewed users to gather their feedback about the Instant Annotation concept. The results pointed to three different design use cases and led us to envision four general design features that we will explore in our ongoing work. We discuss the cross-cultural communication problem, findings from the interview study, the current design and future directions.