In conversations between immigrants and officials, problems of understanding are often noticeable. About 280 recordings realised at the Argentine Aliens' Department and at several public authorities in Germany show that knowledge divergences regarding linguistic, cultural and institutional knowledge result in (sometimes grave) difficulties of understanding – even if the interactants speak the same mother tongue. The German–Argentine comparison provides the possibility to examine the role of language in intercultural communication more accurately because – in contrast to the situation in Germany – the majority of immigrants in Argentina speak the same mother tongue as the receiving country but they still hail from very different cultural areas. This shows that cultural contact cannot – as is often done in western approaches – be equated with language contact. Further, as the first results show, understanding problems seem to be not only a matter of ‘knowledge’ but also of the interactional management of social roles and discourse strategies. The interactants apply strategies of negotiation: attempts to level the relation between the interactants, attempts to constitute a hierarchical relation and attempts to reverse the hierarchical relation – sometimes with conflictuous consequences.