Introduction: Subjects with altered lingual frenulum may have difficulty speaking, chewing, and swallowing. Acoustic analysis allows for inferring the mechanisms of speech production, such as the tongue position on the horizontal and vertical axes and the jaw position. Aim: The aim is to compare formant frequencies (F1 and F2) for seven oral vowels in Brazilian Portuguese (BP), when produced by individuals who had a lingual frenectomy, pre- and post-surgical periods (a minimum six-month interval). Methods: There were seven subjects ranging in age from 6y3m to 14y7m, who were assessed and diagnosed with lingual frenulum alteration and the need for frenectomy was indicated, were selected and participated in two collections of speech data: (a) pre- surgery and (b) post-surgery. The speech samples consisted of words containing the seven vowels of BP which were acoustically analyzed in the software PRAAT, and the F1 and F2 measures were taken. The data were statistically analyzed (ANOVA) for the different vowels in the moments (a) and (b). Results: Acoustic measurements revealed significant differences between the pre-and post-surgical period (six months) when compared to F1 for vowels [a] (p = 0.018), [e] (p = 0.018) and [u] (p = 0.049) and F2 for vowels [e] (p = 0.026) and [u] (p<0.001). Conclusion: F1 and F2 values indicated that the movement of the tongue improved after lingual frenectomy, revealing greater anterior mobilization but limited height range.


lingual frenum, speech disorders, vowel, acoustic analysis