This paper examines the transformation of tonalities in the Central Switzerland village of Muotatal, a small region attracting the focus of ethnomusicologists for harboring and conserving a unique style of yodel, called juuz. The longitudinal study compares three samples of field recordings, collected by Sichardt (sample 1, 1936), Zemp (sample 2, 1979) and Wey (sample 3, 2017). Pitch data are retrieved for the three samples, each consisting of 8 to 10 pieces of solo yodel and over 600 single intervals. As the melodies are organized in horizontal rather than vertical relations, the distribution of pitch is analyzed based on neighboring intervals. The three samples are compared in order to observe transformations the tonal systems have undergone during the time intervals of about 40 years each. The key findings demonstrate a shift of tonality toward equal temperament over the periods observed. While characteristic neutral intervals (seconds, thirds, sixths, sevenths) prevail in the first sample, they are replaced by just and equal-tempered intervals in samples 2 and 3. The findings support the hypothesis that the institutionalization of music pedagogy and four-part choir singing prompted the demise of traditional tonal aesthetics in Alpine valleys.