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PURPOSE Research studies of maximum phonation time, have questioned its validity and value as a tool to assess laryngeal competence. This study proposes a fresh look at phonation time, from a different perspective. The interrelationships of the durations between semiocclusion vs. open vocal tract (/s/-/z/ vs. /a/) and voiced vs voiceless (/z/-/a/ vs. /s/) sound are examined to determine whether this approach might provide additional clinical insight into the respiratory phonatory efficiency of patients. METHODS Comfortable sustained phonat