Figure 4.

Principles of designed rhythm features. Syllable gaps (“x” marks) were determined as the duration between two subsequent syllables (Δt) at the time of their occurrence (t). The regression line of syllable gaps (solid line) describes the rhythm features. The gradient of the line (RA) denotes rhythm acceleration. The RA results in negative values for rhythm acceleration (solid line), positive values for rhythm deceleration (dotted line), and zero values for constant rhythm (dashed line). Rhythm instability (RI) is obtained as the sum of absolute deviations of each observation in term of gasp duration (Δt) from the regression line (epsilon) and is weighted to the total speech time.