People are prone to fear and are suspicious of what they don’t understand. Same goes for having a non-native or foreign accent: it affects our perception of people. For example, since 9/11 a French accent carries with it a certain stigma about political views.
Hardly earth shattering news. In “Why Don’t We Believe Non-native Speakers? The Influence of Accent on Credibility,” author Shiri Lev-Ari makes the case that “Accent might reduce the credibility of non-native job seekers, eyewitnesses, reporters or people taking calls in foreign call centers.” Again this is mostly common sense but also hardly absolute.
When reaching a call center for customer service, most would prefer to speak to someone who both understands and speaks the same language. It has less to do with finding someone not credible and more with trying to avoid the frustration of not being able to communicate. In certain cases, having a non-native accent can actually be favorable. A male with a European accent is typically portrayed in movies as being able to intrigue and charm the ladies. Although a fictional character, James Bond comes to mind.
In college, my physics professor had a strong non-native accent (German).
The foreign accent did not take away but actually added a layer of credibility to the lectures.
It appears then, that what really matters is the connotation associated with the non-native accent and this will vary greatly from person to person and region to region.
Call me gullible but I believed this girls all 21 times.
Here’s a native speaker and yet not very credible.
The facial expressions and terms “such as. . . ” give her away: watch video.
And just for fun here’s a Persian accent.
and 5 Boroughs of NYC accents.