An acoustic camera approach to studying nasality in speech: The case of Polish nasalized vowels

Abstract

The purpose of this research is to introduce an acoustic camera method to analyze nasality in speech. The input information is generated using an acoustic camera device composed of a 16-channel audio recorder with a microphone array, a high-speed video camera, and Carstens articulograph (model AG500). The linearly constrained minimum variance algorithm is used to provide illustrations of the spatial acoustic field distribution. Acoustic pressure distribution is determined as related to the location of oral, nasal, and oronasal resonances, as well as the root mean square value of the pressure. Durations of particular types of resonances activated in the course of speech sound production are also specified. An example application of the method is discussed for Polish nasalized vowels. The internal structure of the vowels is heterogeneous and involves alternate or simultaneous activation of oral and nasal resonances. The order of appearance of these resonances and their percentage share in the realization of the vowels is determined based on the spatial distribution of the acoustic field. The vowels' structure is demonstrated to be even more complex than suggested in former studies. Furthermore, the proportion of nasality is found to vary significantly between the vowels [ɛw̃] and [ɔw̃].

Schlieren imaging and video classification of alphabet pronunciations: exploiting phonetic flows for speech recognition and speech therapy

“…Additionally, when synergized with machine learning, this method can devise optimal, patient-specific therapy to correct speech disorders. It is noted that while several studies have used schlieren imaging to study speech flows [ 26 , 29 , 30 ], none have applied it to speech therapy, focusing instead on the flow intensity of nasal/oral vowels in different languages (German [ 26 ], Polish [ 29 ], and French [ 30 ]). Harvey et al [ 31 ] attempted to recover physical audio signals from high-speed schlieren images, but this approach may be limited to shockwaves generated by events such as clapping hands, snapping belts, and cracking towels, where high-frequency signals dominate.…”

“…Furthermore, the flow variations following lip closure, as described in other studies [ 27 , 28 ]. Lorenc et al [ 29 ] used an acoustic camera approach to investigate Polish nasalized vowels and suggested that the acoustic pressure distribution was dependent on the resonance location (i.e., nasal, oral, velopharyngeal, etc.). The sequence and percentage share of oral and nasal resonances were also determined from the acoustic field of Polish nasalized vowels.…”

Normative Values of Nasal Resonance: Preliminary Data for Polish Working-Age Adults

“…Gąsiorek's data were recorded and collected on an analogue device. It has been found that the colloquial speech test, containing only oral sounds (test VII), correlates best with the degree of nasalance [10]. In general, the results obtained by Gąsiorek averaged 15.2% while in colloquial speech they averaged 25.6% [4,6].…”

Digital measurement of nasal resonance in the adult Polish population

“…Wprowadzenie badań obiektywnych do diagnostyki zaburzeń mowy jest szczególnie przydatne nie tylko przy stawianiu rozpoznania, lecz także w celu usprawnienia procesu leczniczo-rehabilitacyjnego [4]. Jak wynika z przeglądu literatury, dostępne są coraz nowocześniejsze metody oceny mowy [17,18]. W praktyce klinicznej na oddziałach otolaryngologicznych i foniatrycznych najczęściej stosowane są metody akustyczne i ciśnieniowo-akustyczne.…”