Perceptual Sensitivity to Tonal Alignment in Nuer

Area of Science:

• Phonetics and Phonology
• Psychoacoustics
• Linguistic Perception

Background:

• Tonal languages rely on pitch variations for lexical meaning.
• Previous research on the Just Noticeable Difference (JND) suggests a higher threshold for tonal timing perception in non-tonal language speakers.
• The perceptual threshold for differentiating tonal contours (Falling vs. Low tones) is not well-established, particularly for speakers of specific tone languages.

Purpose of the Study:

• To investigate the perceptual threshold for distinguishing between Falling and Low tones in the West Nilotic language Nuer.
• To measure the sensitivity of Nuer native speakers to subtle variations in tonal timing (F0 fall alignment).
• To compare the observed perceptual sensitivity with established JND values from studies on non-tonal languages.

Main Methods:

• A perception experiment was conducted with 30 native speakers of Nuer.
• Stimuli involved manipulated timing of the fundamental frequency (F0) fall following a High tone.
• The threshold for shifting tone perception from 25% to 75% was measured.

Main Results:

• Nuer listeners demonstrated remarkable sensitivity, requiring an average of only 19ms to differentiate between melodic shapes (Falling vs. Low tones).
• In some instances, a Just Noticeable Difference (JND) as small as 13ms was observed.
• This fine-grained sensitivity is significantly lower than the previously reported 50ms threshold for tonal timing in non-tonal language speakers.

Conclusions:

• Native speakers of the Nuer language possess an exceptionally high degree of perceptual sensitivity to tonal timing.
• The findings suggest that experience with a tone language may significantly lower the JND for tonal timing perception.
• This study highlights the crucial role of linguistic background in shaping auditory perception of pitch contours.