The three mainland Scandinavian languages (Danish, Swedish and Norwegian) are so closely related that the speakers mostly communicate in their own languages (semicommunication). Even though the three West Germanic languages Dutch, Frisian and Afrikaans are also closely related, semicommunication is not usual between these languages. In the present investigation, results from intelligibility tests measuring the mutual intelligibility of Danish, Norwegian and Swedish were compared with results of similar tests of mutual intelligibility between speakers of Dutch, Frisian and Afrikaans. The results show that there are large differences in the level of intelligibility depending on test group and test language. Correlations between the intelligibility scores and linguistic distance scores showed that intelligibility can to a large extent be predicted by phonetic distances, while intelligibility is less predictable on the basis of lexical distances. (Contains 12 notes, 6 tables and 6 figures.)