Non-native speech is harder to understand than native speech. We demonstrate that this “processing
difficulty” causes non-native speakers to sound less credible. People judged trivia statements such as “Ants
don't sleep” as less true when spoken by a non-native than a native speaker. When people were made aware
of the source of their difficulty they were able to correct when the accent was mild but not when it was
heavy. This effect was not due to stereotypes of prejudice against foreigners because it occurred even though
speakers were merely reciting statements provided by a native speaker. Such reduction of credibility may
have an insidious impact on millions of people, who routinely communicate in a language which is not their
native tongue