A few studies published in the Proceedings of the National Academy of Sciences purport that we have biases towards class from even a few seconds of speech.
This is concerning but not unheard of. There’s subjective standards in the English language which people bias as being a perceived higher social class. It changes how we consider others. Another followup study examines how this may affect hiring managers’ assessment of qualifications.
However, the research is even more interesting because it shows that pronounciation cues in speech gives a more accurate assessment as to someone’s social status than the content.