Revisiting pitch jumps: F0 ratio in Seoul Korean

Pitch tracking algorithms can show upward or downward jumps in F0 by one octave. These “octave jumps” are sometimes thought of as pitch-tracking “errors”, in the sense that they constitute a “mistake” in the algorithm. Using Praat software, we discuss the point (which has been made before) that measured octave jumps often actually reflect genuine changes in periodicity and glottal-fold vibration. We illustrate this with the example of creaky voice in fortis stops in Seoul Korean. We argue (1) that when the goal is to capture periodicity or vocal-fold vibration, pitch-tracking algorithms capture F0 well, with pitch jumps possibly reflecting an important language-specific feature, and (2) that ignoring such jumps (due to assuming an error) could lead to misrepresentation of the properties of the language. To quantify these real F0 jumps, we introduce the notion of the “F0 ratio”, which identifies potential F0 jumps and helps to chart the frequency of pitch jumps in a language.