The internal structure of the Austronesian languages is complex. The family consists of many similar and closely related languages with large numbers of dialect continua, making it difficult to recognize boundaries between branches. The first major step towards high-order subgrouping was Dempwolff's recognition of the Oceanic subgroup (called "Melanesisch" by Dempwolff). The special position of the languages of Taiwan was first recognized by André-Georges Haudricourt (1965), who divided the Austronesian languages into three subgroups: Northern Austronesian (= Formosan), Eastern Austronesian (= Oceanic), and Western Austronesian (all remaining languages).