Ten normal speaking adults (five male, five female) performed three speaking tasks during conditions of monaural and binaural masking with and without complete palatal appliances. Significant effects on the subjects' articulation were found for the factors of masking type, palatal appliance and speaking task. No significant effects were found for monaural right- versus monaural left-ear masking or sex of the speakers. The findings are similar to previous results using binaural masking and indicate that the disruptive effect of monaural masking on the articulation of adult subjects is approximately midway between the effects of no masking and binaural masking. It is suggested that the lack of a significant effect for right-ear versus left-ear monaural masking may be due to the high degree of automatization which subjects possessed for the stimuli used in the speaking tasks.