Phonetic characteristics of German unstressed vowels: The case of opa vs Oper

Kohler [Einführung in die Phonetik des Deutschen (Erich Schmidt Verlag, Berlin, Germany, 1995)] stated that German [ɐ] and [a] in unstressed syllables are merging. The present study tested this hypothesis. The contrast was found intact word-internally and word-finally. Neighborhood density enhanced its phonetic characteristics, but no effects of frequency and conditional probability were found.