COMFORTABLE EFFORT LEVEL REVISITED

The purpose of this study was to measure the variability of frequency and intensity of speech, using multiple voice samples obtained over a period of time at a speaker's ''comfortable effort level.'' Variabilit y in vocal output within and across several experimental sessions was assessed from measures of speaking fundamental frequency (SFF) and voc al intensity for utterances repeated three times a day over a 3-day pe riod. Three distinct age groups of men and women-young, middle-aged an d elderly-repeated the vowel /a/, read a standard passage, and spoke e xtemporaneously during each experimental session. Results indicated th at variability in SFF and intensity were present across experimental s essions, age groups, gender, and speaking samples. Generally, group me ans indicated that similar to+/-1 semitone of variability for SFF and similar to 2 db sound pressure level (SPL) variation in vocal intensit y from any one experimental session to the next could be expected; ind ividual variations within any group may reach two semitones and 6 db S PL.