Variations in velar closure location
Variations in velar closure location are a feature of the velar flap during speech production. They can be quantitative or qualitative. For example, a person with marginal velopharyngeal incompetence may have a more posterior closure compared to a person with an anterior closure.
Velar closure location and amplitude are regulated by a complex and physiologically variable mechanism. The movements of the LPWs, PPWs, and vellum determine the degree of velar closure. During speech and swallowing, the velum moves in a superior and posterior direction and contacts the PPWs and LPWs.
The LPW and velum also act in synchrony to enhance the velum’s movement. In addition, a phonetic context may affect the characteristics of velar closure for vowels. For example, voiceless stops are more resistant to nasalization than liquid or nasal vowels. The preceding vowel may also influence the location of the velar closure. However, more research is needed to understand the extent of these influences.
Influence of surrounding vowels on velar closure location
The effect of surrounding vowels on the location of velar closure has been studied using ultrasound imaging. Using this technique, the angle of closure is measured along the x-axis and is correlated with the vowel F2. The smaller the value of F2, the more frontward the tongue will be during closure.
We found that in all participants, the proximity of surrounding vowels strongly influenced velar closure location. This was particularly true for non-front vowels. The BIC analysis also revealed individual differences in pattern of variability. This suggests that there might be two distinct articulatory targets for velar closure location.
These differences were not statistically significant, but were consistent across all participants. Furthermore, they showed a direct correlation between the location of velar closure and the location of the tongue body for the following vowel. This finding supports the virtual target model of stop consonant production, which argues that these two allophones can influence the location of the velar closure.
Influence of tongue body position on velar closure location
The position of the tongue, velum, and epiglottis during speech are all affected by body position. We investigated this through videofluoroscopic data collected from 12 healthy adults in supine and upright positions. We found that these factors influenced the location of the velum and the target sound, as well as the vowel formant structure.
