Articulatory Analysis and Acoustic Modeling: Articulatory To Acoustic ModelingUltrasound As a Tool For Speech ResearchMethodologies Used to Investigate Laryngeal Function and Aerodynamic Properties of SpeechOn The Acoustics and Aerodynamics of Fricatives

This article describes theory and research methods employed for articulatory, acoustic, and aerodynamic analysis of speech. One of the theories, dispersion-focalization theory (DFT), combines two ideas that include focalization and contrast maximization. Focalization is a property that emerges from acoustic model nomograms and refers to points where constriction placement results in formants being close to each other (focal points). The theory distinguishes between independent and non-independent secondary contrasts. Independent secondary contrasts are secondary contrasts that do not interact with the primary vowel contrasts, while non-independent contrasts are secondary contrasts that affect the primary ones. The principle of distinctive region model (DRM) is that different regions of the vocal tract have uniform acoustic behavior. The results of DRM are based on how formation and release of constrictions affect the formants at different locations within the vocal tract. The DRM theory of linguistic contrast is based on the pseudo-orthogonality of the discrete regions and on a dynamic articulatory-acoustic principle stating that segments are preferred, which allow for the least motion from one segment to another, while maximizing contrast. Ultrasound imaging is increasingly been used to address specifically phonological questions. The technology is also used to examine the status of excrescent schwas in various phonological environments.