Time-series f0 analysis of contrastive tones: the case of Livonian natural speech

Livonian is a Finnic language that differentiates between two contrastive phonological word tones: the broken tone and the plain tone. The broken tone is similar to the Danish stød in some respects and is said to be part of the word tone systems of the phonologies of languages in the Baltic region. The most characteristic acoustic reflexes of words with stød are the pitch contour's rising-falling or falling shape and (occasional) creaky phonation. These characteristics have been documented in controlled speech (e.g., Teras & Tuisk 2009). This paper presents findings for the tonal contrast in Livonian utterances in natural speech elicited from ten native speakers. To analyze the f0 contours associated with the stød contrast, generalized additive models (GAMs) were used. Interestingly, the findings show that the only clear difference occurs in disyllabic words in the speech of men. Men have a clearly rising-falling f0 contour in disyllabic words with stød, but a level-falling contour in words without stød. Women have a falling contour both in words with and without stød, i.e., the contrast appears to be neutralized in spontaneous speech for this group. The results indicate accommodation to the surrounding majority language of Latvian.