The purpose of this longitudinal study was to predict /r/ acquisition using acoustic signal processing. 19 children, aged 5-7 with inaccurate /r/, were followed until they turned 8 or acquired /r/, whichever came first. Acoustic and descriptive data from 14 participants were analyzed. The remaining 5 children continued to be followed. The study analyzed differences in spectral energy at the baseline acoustic signals of participants who eventually acquired /r/ compared to that of those who did not acquire /r/. Results indicated significant differences between groups in the baseline signals for vocalic and postvocalic /r/, suggesting that the acquisition of certain allophones may be predictable. Participants’ articulatory changes made during the progression of acquisition were also analyzed spectrally. A retrospective analysis described the pattern in which /r/ allophones were acquired, proposing that vocalic /r/ and the postvocalic variant of consonantal /r/ may be acquired prior to prevocalic /r/, and /r/ followed by low vowels may be acquired before /r/ followed by high vowels, although individual variations exist.

The purpose of this study was to explore the relationship between orofacial myofunctional disorder (OMD) and speech production errors of /s/ and /z/. A randomized sample of 32 college-aged participants was analyzed to determine OMD prevalence. Further recruitment took place for those that had current speech errors or had a history of speech therapy, totaling 39 participants (ages 18-36). Subjects participated in an evaluation (ranging from 0:18:27 to 0:30:08) where OMD classification was determined through the validated 2010 Expanded Orofacial Myofunctional Evaluation with Scores protocol (OMES-E), and speech production errors were assessed through spontaneous speech and a reading sample. Through a descriptive analysis of the first 32 participants, greater prevalence of OMD was seen in participants who exhibited moderate to severe speech errors than those with mild/subclinical and no speech errors. Results from the 39 participants indicated a significant correlation between OMD classification and speech errors. Further analysis showed speech errors were significantly correlated with the OMES-E subtests of physical features/posture and mobility. Results suggest that OMD may be a contributing factor to persistent speech errors in college-aged students. Further research may indicate that OMD characteristics need to be treated alongside speech sound disorders to aid in successful remediation of speech errors in individuals who exhibit both OMD and speech errors.