Purpose: The aim of this study was to evaluate the understanding of English sentences produced by native (English) and nonnative (Spanish) talkers by listeners with normal hearing (NH) and listeners with cochlear implants (CIs). Method: Sentence recognition in noise was measured in adult subjects with CIs and subjects with NH, all of whom were native talkers of American English. Test sentences were from the Hearing in Noise Test (HINT) database and were produced in English by four native and eight nonnative talkers. Subjects also rated the intelligibility and accent for each talker. Results: The speech recognition thresholds in noise of subjects with CIs and subjects with NH were 4.23 dB and 1.32 dB poorer with nonnative talkers than with native talkers, respectively. Performance was significantly correlated with talker intelligibility and accent ratings for subjects with CIs but only correlated with talker intelligibility ratings for subjects with NH. For all subjects, performance with individual nonnative talkers was significantly correlated with talkers' number of years of residence in the United States. Conclusion: CI users exhibited a larger deficit in speech understanding with nonnative talkers than did subjects with NH, relative to native talkers. Nonnative talkers' experience with native culture contributed strongly to speech understanding in noise, intelligibility ratings, and accent ratings of both listeners with NH and listeners with CIs.