Evidence for the interdental/alveolar contrast in the Mapudungun spoken on the coast: an acoustic and statistical study

Abstract

Most previous research on Mapudungun has argued for the existence of a phonemic contrast

between interdental—[l], [ n], and [t]—and alveolar segments—[l], [n], and [t]2 (e.g., Echeverría,

1964; Salas, 1976). However, some studies have challenged this hypothesis

(e.g., Cro-ese, 1980; Smeets, 1989; Salamanca & Quintrileo, 2009), particularly when analysing data from

Mapudungun spoken in areas with a strong Spanish presence. This study aims to provide

evidence to determine whether this contrast is present in the speech of 19 participants from

Toltén and Mariquina. In order to do this, locus equations were used (Sussman, McCaffrey, &

Matthews, 1991; Sussman, Hoemeke, & Ahmed, 1993), as well as several types of regression

analyses. These techniques aimed to ascertain whether statistically significant differences

exist between the acoustic correlates of place of articulation obtained from interdental and

alveolar segments, in three manners of articulation: lateral, nasal and voiceless plosive. The

effects on the acoustic data of the variables vowel and sex was also explored. The results

of analysing 3437 tokens suggested that there is evidence to support the hypothesis of a

phonemic contrast for lateral and plosive consonants, but not for nasals; also, there was a

statistically significant effect of vowel and sex. In sum, these results suggest that the phonemic

contrast between interdental and alveolar nasals is weakening, which has important

implications for Mapudungun dialectology. From a methodological perspective, this study

highlights the importance of including techniques from acoustic phonetics and inferential

statistics in the study of Chilean vernacular languages.