This study investigated the effects of noise and filtering on the intelligibility of speech produced during simultaneous communication (SC). Four normal hearing, experienced sign language users were recorded under SC and speech alone (SA) conditions speaking Boothroyd's forced-choice phonetic contrast material designed for measurement of speech intelligibility. Twenty-four normal hearing listeners audited the speech samples produced by the four speakers under the SC and SA conditions, three listeners in noise and three listeners in filtered listening conditions for each of the four speakers. Although results indicated longer sentence durations for SC than SA, the data showed no difference in the intelligibility of speech produced during SC versus speech produced during SA under either the noise or filtered listening condition, nor any difference in pattern of phonetic contrast recognition errors between the SA and SC speech samples in either listening condition. This conclusion is consistent with previous research indicating that temporal alterations produced by SC do not produce degradation of temporal or spectral cues to speech intelligibility or disruption of the perception of specific English phoneme segments. Learning outcomes: As a result of this activity, the participant will be able to (1) describe simultaneous communication; (2) explain the role of simultaneous communication in communication with children who are deaf; (3) discuss methods of measuring speech intelligibility under filtered and noise conditions; and (4) specify the ability of listeners to perceive speech produced during simultaneous communication under noise and filtered listening conditions.