Despite similar phonetics, phonological analyses suggest a differential tongue height specification of the vowels /i/ and /e/ in Turkish and German. This was tested by use of the mismatch negativity (MMN), an automatic change detection response of the brain, which was recorded for Turkish-German bilinguals and German listeners. Our results support the predictions about the differential specification of tongue height features, i.e. in Turkish /e/ is specified for [LOW] and not underspecified as in German; whereas /i/ is underspecified for height in Turkish and specified for [HIGH] in German.