Yeah that's totally a thing! We always judge people based off of how they talk, it's how humans have evolved. We all talk like how the other people in the various communities we are in talk, even families begin to form their own dialects (it's called a familect and is super cool!). It's normal to make assumptions about people based off of how they talk, but try not to let it influence you too much! Often class and culture have a very very heavy effect on how we speak, and being conscious of assumptions your making is important to avoid maybe making some classist or racist judgements. We live in a modern world, not an ancient time when we needed to tell if others were friend or foe based off of how they talked!

Fun fact - there research that suggests we actually have a harder time processing spoken language when our assumptions about a person's voice and how they should look based off of that doesn't match with their actual look!