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This paper deals with the measurement of spectral moments of Serbian fricatives. The four spectral moments: centre of gravity, spectral variance, skewness, and kurtosis were measured at the onset of the fricative, on the stable-state part and at the fricative offset. The results show that the highest values for the centre of gravity can be found in non-sibilants, except for the sound [v]. The measurements were taken in both Hertz and Bark scales, and the results show that the Bark scale serves better in distinguishing fricative types. The energy which is generated during the fricatives' production is not evenly allocated in the time-course of the fricative length. Voiced and voiceless fricatives differ in force of articulation within the fricative duration. The greatest factor effects were found to be the place of articulation and phonological voicing. The vowel that follows does not statistically influence the spectral moments’ values, except for the difference in fricative [x] which surfaces as an acoustically different segment before the vowels [i] and [u].

Straipsnyje pirmą kartą lietuvių kalbos trankieji priebalsiai tiriami lokuso lygčių (locus equations) metodu, kuris akustinės fonetikos tyrimuose plačiai taikomas tiek balsių ir priebalsių koartikuliacijos lygiui nustatyti, tiek priebalsių artikuliacijos vietai tirti. Be to, tai pirmasis lyginamasis lietuvių ir latvių kalbų trankiųjų priebalsių tyrimas, atliktas pagal tą pačią metodiką. Straipsnyje pateikiama abiejų baltų kalbų priebalsių akustinė klasifikacija, sukurta remiantis universaliais Tarptautinės fonetikų asociacijos (TFA) sukurtais principais. Abiejų kalbų lokuso lygčių rezultatai lyginami pagal tris kriterijus: balsingumą, palatalizaciją ir artikuliacijos vietą.

In the article, the acoustic features of nasals in Standard Latvian are investigated. The aim of the study is to examine whether some of the spectral properties of nasal murmur (namely anti-formant frequency, as well as frequency and bandwidth of the first nasal formant) can be considered as efficient cues for distinguishing between nasal places of articulation.Speech recordings from 10 native speakers of Standard Latvian, five male and five female, aged 19–39, without any disorders or dialectal traces in their pronunciation, were used for the analysis. Prevocalic nasals [m; n; ɲ] were analyzed in isolated CVC syllables, where C is one of the nasals and V is one of the vowels [i(ː); e(ː); æ(ː); ɑ(ː); ɔ(ː); u(ː)]. The velar [ŋ] — the allophone of the phoneme /n/ — was recorded in postvocalic position in [k]V[ŋks] structure units. 1260 items were analyzed in total.According to the results, the nasals of Standard Latvian can be distinguished by anti-formant frequencies rather efficiently, and the results generally agree with those obtained in previous research of Latvian as well as data reported for other languages. The frequencies and the bandwidths of the first nasal formant are less informative regarding nasal place of articulation and can be used only for distinguishing between [ŋ] and [m; n; ɲ]. Conducting perception tests to assess the auditory relevance of these acoustic features is necessary.

The present paper explores the phenomenon of perturbation of fundamental frequency in fricative obstruents in Serbian. The recordings include two reading conditions of target tokens with initial fricative and all vowels from the Serbian phonetic inventory. Two measurements were performed on the recorded data: the first measurement includes the first five oscillating periods of the post-fricative vowel and the second every centisecond of the first 120 ms of the vowel. We explored the dependence of pitch values on underlying voicing of initial fricatives, vowel quality, place of articulation and phonological context. The quality of the vowel affects the fundamental frequency in a way that high vowels have higher f0 values and the opposite. The place of articulation is not a significant factor of f0 change. More statistically significant results were obtained in reading words in a carrier sentence than reading them in isolation. The contour of f0 is shown to be falling after voiceless, and falling or level after voiced fricatives, except one case of rising f0 after voiced fricatives. The perturbation effect is found to be 60 ms into the vowel. With this fact in mind, we concluded that f0 perturbation is utilized to enhance the voicing contrast of prevocalic fricatives. The patterning of voiceless unaspirated and voiceless aspirated consonants in other languages classifies the f0 cue as one of the [voice] rather than [spread] features.

This study was conducted with four Palestinian-speaking Broca's aphasics and four normal speakers to examine the production of the fricative /s/ and to analyze the difference in acoustic patterns between the two groups. The acoustic analysis revealed that the Broca's aphasics were able to maintain the phonetic distinction between voiced and voiceless fricatives and did not exhibit voicing or devoicing errors. This result is inconsistent with findings from other languages. The spectral peak of the alveolar /s/ was lower for the aphasic subjects than for the control speakers. The Broca's aphasics displayed a longer duration for /s/ than the control subjects did. The /s/ spectra for the Broca's aphasics were "flatter" than the /s/ spectra for the control speakers and were characterized by a relatively low-frequency energy peak. Substitution errors predominated. In most cases, a one-distinctive-feature error occurred that primarily involved the place of articulation. Generally, the findings of the study suggest that the errors exhibited by Broca's aphasics reflect articulatory movements and articulatory implementation deficits rather than a selection of inappropriate speech segments.