Trillingsindex

Trillingsindex is a term used in phonetic research to describe a composite index intended to quantify the degree to which a trill consonant, such as a rolled r, is realized in a spoken segment. The concept is not standardized across studies and its exact definition can vary depending on the researchers or the language context.

Typically, the trillingsindex combines both articulatory and acoustic indicators. Articulatory measures may include tongue-tip movement amplitude, the velocity of trill cycles, and the frequency of trill alternations per second. Acoustic measures often involve the periodicity and stability of the waveform, spectral characteristics related to rapid alternation, and modulation of voice fundamentals during the trill. These components are usually normalized and aggregated into a single score.

Calculation methods generally follow a two-stage process. First, data are collected with appropriate instrumentation such as ultrasound tongue imaging, electromagnetic articulography, high-speed video, or detailed acoustic analysis. Second, each component is normalized to a common scale (for example 0 to 1) and combined, often through a weighted sum: trillingsindex = w1*A_norm + w2*P_norm + w3*D_norm, where A_norm, P_norm, and D_norm represent articulatory, periodicity, and duration-related sub-indices, respectively, and w1, w2, w3 are chosen weights.

Applications of the trillingsindex include comparative phonetics, dialectology, and speech therapy, where it can aid in quantifying variation in trill realization across speakers or languages. Limitations include the lack of a universal standard, sensitivity to recording conditions, and the need for robust, language-specific validation.

See also: trill (phonetics), speech production, articulatory phonetics.