A configurational approach to the prosody of topic and focus in Egyptian Arabic. Testing the importance of accent-based and utterance-based acoustic cues

Recent research on Egyptian Arabic suggests that topic and focus are realized by different pitch events and that a focus is followed by post-focus attenuation. It is, however, not known how well these structures are discriminated and which are the relevant acoustic cues. We present results from a Random Forest based discrimination between two topic and two focus types, using 62 acoustic cues over the utterance, of which 37 are related to the target accent. All categories are discriminated very well with some confusion between the subtypes. The two most important cues are the velocity of the fall of the target accent and the scaling of the following peak, followed by the amount of fall in the accent and the intensity of the utterancefinal word/syllable. Further important findings are that f0 is especially important to distinguish between target accents and to indicate register lowering, that intensity features are only related to the target word and the last word, and that duration is only relevant in the target accent. This suggests that the target accent is signaled by all acoustic cues, but primarily by a pitch fall, and post-focus attenuation by immediate register lowering and a salient intensity drop at the end of the utterance