Judging someone by their accent tells people more about your hearing than their brain.

An accent carries information about where someone has lived and none at all about how well they think. The reaction happens fast and below the level of decision, which is what makes it worth catching, because left alone it quietly determines who you take seriously. It reveals the listener’s assumptions rather than the speaker’s ability.

Notice the moment your estimate of someone shifts before they have said anything of substance. Then deliberately listen for the content again. It is also worth remembering that anyone speaking your language as their second one is doing something you may not be able to do at all.