Table 1 Key literature results
Tokens | Measures | Oral airflow effect of vowel context | |
|---|---|---|---|
Bucella et al. [10] | Sustained vowels /i, a, u/ | Mean mid-vowel oral airflow amplitude | Significant vowel effect |
Cho et al. [11] | Bilabial stops (fortis, lenis and aspirated) in three real words (same vowel context) | Maximum oral airflow after stop release | Significant effect of stop category (fortis, lenis and aspirated) |
Higgins et al. [21] | Isolated repetitions of /pi/ and /pɑ/, and repetitions of <buy pip again> and <buy pap again> | Mean mid-vowel oral airflow amplitude | No significant intrasubject differences across vowel type |
Higgins et al. [22] | Isolated repetitions of /pi/ and /pɑ/, and repetitions of <buy pip again> and <buy pap again> | Mean mid-vowel oral airflow amplitude | No significant interactions involving the factor of vowel for mean airflow |
Koenig et al. [30] | Repetitions of <poppa popper> and <poppa bopper> | VCV oral airflow signals used to identify voicing onset and offset during stop closure | Some of the stops’ oral airflow signals “did not show abrupt changes associated with vocal-tract closure and release, suggesting lenition or spirantization” ([30], p. 1080) |
Koenig et al. [31] | Voiceless glottal fricative /h/ produced in repetitions of the sentences <a papa hopper>, <a papa hippie> and <a papa hooper> | Oral airflow amplitude at voicing onset and offset during stop closure | “…individual speakers have unique methods of achieving phonatory goals during running speech.” ([31], p. 2535) “… the direction of vowel effects differed across speakers …” ([31], p. 2548) |
Netsell et al. [37] | CV syllables where C was /p/, and V was /i/ or /a/ | Mean mid-vowel oral airflow amplitude | No significant difference between oral airflow for [i] versus [a] |