Multilingual learners possess a larger repertoire of phonetic-phonological parameters, of language awareness and phonological knowledge as well as an increased cognitive flexibility, which supports their acquisition of the phonetics of further foreign languages. This papers shows phonetic similarities between Russian (as L2) and Polish (as L3) which can be used for positive transfer by native speakers of German (L1) learning these Slavic languages. Pedagogical implications concerning the teaching of phonetics for a third language are drawn.