Verbal tone in Mpyemo

This thesis describes the tonal patterns and alternations present in the Mpyemo language (Bantu A.86c – ISO code mcx), with special attention to the verbal system. Rules and autosegmental representations are used to clarify and provide a formal analysis. A tone raising rule causes the underlying two-tone system to display three phonetic levels at the surface. This thesis explores nominalized verbs and verbs in the imperative. In addition, inflected verbs are described, although only a limited set of inflectional morphemes are treated. Thus, I look at verbs with inflectional prefixes for subject agreement, the perfect, and a single verbal auxiliary (a category that includes tense and aspect as well as lexical morphemes). I do not attempt a treatment of negation, questions, verbs with multiple auxiliaries, or those with causative or reflexive suffixes. Verbal auxiliaries are subdivided into three groups according to their compatibility with the perfect. Floating tones occur at three different morpheme boundaries and distinguish between indicative mood and subjunctive mood. Nominal tone is also briefly discussed, in order to show parallels with verbal tone and to account for the behavior of nouns as verbal objects

Automatic speech-to-background ratio selection to maintain speech intelligibility in broadcasts using an objective intelligibility metric

While mixing, sound producers and audio professionals empirically set the speech-to-background ratio (SBR) based on rules of thumb and their own perception of sounds. There is no guarantee that the speech content will be intelligible for the general population consuming content over a wide variety of devices, however. In this study, an approach to automatically determine the appropriate SBR for a scene using an objective intelligibility metric is introduced. The model-estimated SBR needed for a preset minimum intelligibility level was compared to the listener-preferred SBR for a range of background sounds. It was found that an extra gain added to the model estimation is needed even for listeners with normal hearing. This gain is needed so an audio scene can be auditioned with comfort and without compromising the sound effects contributed by the background. When the background introduces little informational masking, the extra gain holds almost constant across the various background sounds. However, a larger gain is required for a background that induces informational masking, such as competing speech. The results from a final subjective rating study show that the model-estimated SBR with the additional gain, yields the same listening experience as the SBR preferred by listeners