Ukrainian in prosodic typology of world languages

Introduction. This study presents an experimental investigation of the rhythmic organization of Ukrainian speech within the framework of prosodic typology of world languages. The research addresses the longstanding problem of classifying Ukrainian according to rhythm type, particularly in relation to the opposition between syllable-timed and stress-timed languages. While such classifications have been widely applied to major European languages, Ukrainian has not previously been systematically examined using acoustic criteria. The aim of the study is to determine the rhythmic type of Ukrainian by analyzing temporal correlates of speech rhythm, specifically the duration of syllables and interstress intervals, with consideration of the effect of speaking rate.

Methods. The empirical material consists of recordings of standard Ukrainian speech divided into two experimental groups: moderately paced read speech and fast spontaneous speech. Speaking rate is operationalized as the number of syllables per second, with moderate tempo defined as 3.5–5.5 syllables per second and fast tempo as 6.5–8.5 syllables per second. The dataset includes 400 syllables and 400 interstress intervals, ensuring statistical reliability at the 95% confidence level. Acoustic measurements of segment duration are carried out using instrumental phonetic methods. Temporal variability is quantified by means of standard deviation and coefficient of variation, and a coefficient of isochrony (IsCo = 100% – VarCo) is introduced to evaluate the relative temporal regularity of rhythmic units.

Results. The results demonstrate that the average duration of syllables ranges from approximately 195 ms in moderate speech to 125 ms in fast speech, with variability between 36% and 39%. Stressed syllables are consistently longer than unstressed ones: about 240 ms vs. 175 ms in moderate speech and 145 ms vs. 110 ms in fast speech, corresponding to a difference of 28–39%. Interstress intervals show greater temporal stability, with mean durations of 570 ms in moderate speech and 380 ms in fast speech, and a constant variability of 30% across tempo conditions. The calculated isochrony coefficients indicate that syllables exhibit 61–64% isochrony, whereas interstress intervals reach approximately 70%, exceeding syllabic isochrony by about 13%.

Discussion. The findings indicate that speech rhythm in Ukrainian is not characterized by strict periodic isochrony but rather by quasi-periodic temporal organization. The higher and more stable isochrony of interstress intervals compared to syllables suggests that rhythmic structuring is primarily organized around stress groups rather than syllabic units. At the same time, the relatively high degree of syllabic isochrony points to a mixed rhythmic profile. These results support a continuum-based interpretation of prosodic typology, where languages may exhibit intermediate characteristics rather than belonging to discrete rhythm classes. The influence of speaking rate is shown to affect the absolute duration of segments but not the relative variability of interstress intervals, which remain stable across tempo conditions.

Conclusion. The study establishes that Ukrainian occupies an intermediate position in prosodic typology, with a dominant tendency toward stress-timed rhythm due to the greater isochrony of interstress intervals and the functional role of stress in temporal organization. The results provide quantitative evidence for classifying Ukrainian as a predominantly stress-timed language with mixed features and highlight the importance of incorporating speaking rate into models of speech rhythm. The study contributes to the refinement of cross-linguistic rhythmic classification and offers a methodological basis for further comparative phonetic research.