This study examined the effects of laryngeal activity on articulation by comparing the articulatory kinematics of the /i/ and /u/ vowels produced in different speaking conditions (loud, comfortable, soft and whisper). Participants included 10 males and 10 females with no history of communication disorders. The participants read six stimulus sentences in loud, comfortable, soft and whispered conditions. An electromagnetic articulograph was used to track the articulatory movements. The experimenters selected the sentence We do agree the loud noise is annoying from the other utterances and the words we do agree were segmented from the sentence. We do agree was chosen because of the tongue and lip movements associated with the retracted and rounded vowels. Results reveal the soft condition generally has smaller and slower articulatory movements than the comfortable condition, whereas the whispered condition shows an increase in size and the loud condition shows the greatest increase in both size and speed compared to the comfortable condition. The increase in the size of the movements in whispered speech may be due to unfamiliarity as well as a decrease in auditory feedback that requires the speaker to rely more on tactile feedback. These findings suggest that adjusting laryngeal activity by speaking more loudly or softly influences articulation; this may be useful in treating both voice and articulation impairments.

The current study examined the effects of three speech conditions (voiced, whispered, mouthed) on articulatory kinematics at the sentence and word level. Participants included 20 adults (10 males, 10 females) with no history of speech, language, or hearing disorders. Participants read aloud six target utterances in the three different speaking conditions while articulatory kinematics were measured using the NDI Wave electromagnetic articulograph. The following articulators were examined: mid tongue, front of tongue, jaw, lower lip, and upper lip. One of the target utterances was chosen for analysis (It's time to shop for two new suits) at the sentence level and then further segmented for more detailed analysis of the word time. Results revealed a number of significant changes between the voiced and mouthed conditions for all articulators at the sentence level. Significant increases in sentence duration, articulatory stroke count, and stroke duration as well as significant decreases in peak stroke speed, stroke distance, and hull volume were found in the mouthed condition at the sentence level when compared to the voiced condition. Peak velocity significantly decreased in the mouthed condition at the word level, but overall the sentence level measures were more sensitive to change. These findings suggest that both laryngeal activation and auditory feedback may be necessary in the production of normally articulate speech, and that the absence of these may account for the significant changes between the voiced and mouthed conditions.

The current study examined the effects of bite blocks on articulatory kinematics when producing /r/ within a phrase. Participants consisted of 20 young adults (10 males, 10 females) with no speech, language or hearing disorders. Participants produced the carrier phrase, I say __ with the nonsense words /əri/ (high front vowel), /əræ/ (low front vowel), /əru/ (high back vowel), /ərɑ/ (low back vowel). A Northern Digital Instruments Wave electromagnetic articulograph measured the articulatory movements while the speaker produced the stimuli in two conditions (Pre bite block and post bite block). Bilateral bite blocks were made using Express dental putty, which is a silicone impression material, in order to create an inter-incisal gap of 10 mm. The hull area (i.e., a boundary enclosing the total distance the sensor traveled during the target phrase) of the data for each sensor (i.e., tongue back, tongue mid, tongue front, lower lip, mandibular central incisor) was calculated for the individual nonsense words /eɪərɑ/, /eɪəræ/, /eɪəri/, and /eɪəru/. Results revealed kinematic differences across vowel phrases and between genders. The hull area of the tongue and jaw were significantly different for the vowel phrases /eɪəræ/, /eɪəri/, and /eɪəru/ compared to /eɪərɑ/. The hull area for the jaw for /eɪərɑ/ was significantly larger than the other vowel phrases. The between-gender analyses showed larger hull areas for males than females. Different motor equivalent strategies for tongue movements were observed when speakers produced /eɪərɑ/ and there were individual differences in compensating for the presence of the bite block

The current study examined the effects of bite blocks on articulatory kinematics when producing diphthongs /ɑɪ/ and /ɑʊ/ within a phrase. Participants consisted of 20 young adults (10 males, 10 females) with no speech, language or hearing disorders. Participants produced the diphthongs in the carrier phrase Im an owl that hoots. A Northern Digital Instruments Wave electromagnetic articulograph measured the articulatory movements while the speaker produced the stimuli in two conditions (pre bite block insertion and post bite block insertion). Bilateral bite blocks were made using Express dental putty, which is a silicone impression material, in order to create a 10 mm inter-incisal gap. Marker distance, maximum speed, and jaw contribution to tongue movement for three sensors (tongue back, tongue mid, tongue front) were calculated for the diphthongs segmented from the carrier phrase. F1 and F2 transitions and rate were also calculated for each diphthong. Results revealed kinematic differences during diphthong production after the bite block was inserted. Tongue movements independent from the jaw increased after the bite block was inserted, especially during production of the diphthong /ɑʊ/. Bite block by gender interactions during production of the diphthong /ɑɪ/ revealed larger and faster initial movements for males. The results did not reveal any significant acoustic changes other than a longer transition duration. Kinematic adjustments were sufficient to maintain overall similar acoustic output before and after bite block insertion.