The obligatory phonotactic constraint of Dorsal Fricative Assimilation in German is activated and applied during automatic speech processing

• ¹ Institute of Psychology 1, University of Leipzig, Germany
• ² Centre for General Linguistics (ZAS), Germany

In auditory speech processing, implicit linguistic knowledge is activated and applied on phonetic and segment-related phonological processing even if the perceived sound sequence is outside the focus of attention. In this study, the effects of obligatory language-specific phonotactic restrictions on pre-attentive auditory speech processing were investigated. To this end the Mismatch Negativity component of the human event-related brain potential was used. In German grammar, the occurrence of the velare [+back] and the palatal [-back] dorsal fricatives is limited by the phonotactic restriction of Dorsal Fricative Assimilation (DFA). DFA demands a vowel and a following dorsal fricative to agree in articulatory backness [±back], e.g. “Koch” (cook) or “echt” (real). Combinations of a back vowel and a following palatal dorsal fricative within a syllable lead to phonotactically incorrect sequences. For the passive oddball stimulation, three phonotactically correct VC syllables and one phonotactically incorrect syllable violating DFA were used. Stimuli were contrasted pair-wise in oddball blocks such that they differed regarding their vowel while sharing the fricative. Oddball contrast 1: [e + coronal sibilant (as in “fresh”)] versus [o + coronal sibilant (as in “posh”)]; Oddball contrast 2: [e + palatal dorsal fricative (as in German “echt”)] versus [o + palatal dorsal fricative (which is incorrect in German)]. Apart from an early MMN response which is attributable to the change of the initial vowel and which was elicited by all deviants as predicted, we observed another negative deflection in the event-related potential elicited by the phonotactically violated deviant only. This negativity occurs approximately about 250ms after the phonotactic violation became detectable. Since it can not be attributed to any phonetic or segmental difference between standard and deviant we consider this late negativity to reflect the effect of a phonotactic evaluation process. Our finding suggests that implicit phonotactic knowledge is activated and applied even outside the focus of the participants’ attention.