Immigrants tend to underperform in the labour market i.e. they are paid less than one might expect. This could be for several reasons. Prejudice is a possibility or their human capital may not be sufficiently valued if there is uncertainty about the quality of their education. The paper below documents another angle, namely that their accent may put them at a disadvantage. After all, foreigners talk funny, y'all know what I mean?
Why don't we believe non-native speakers? The influence of accent on credibility
S Levi-Ari, B.Keysar
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.
Journal of Experimental Social Psychology 46(6), 2010, 1093-1096