Although there are millions of people speaking the same language, every individual utilises their words differently, creating a somewhat new dialect for each being. The way that this unique dialect is crafted depends on the environment and people that the individual has been raised around, as an impressionable child, you take examples of the older authoritative figures in your life and display a mix of their tongue, making use of a combination of their slang, words and languages, overall. If a child is raised in a more casual, background, in a country with a very distinct accent, they will hold that for the rest of their lives, although the amount is variable, on the other hand, if a child is brought up in a formal environment, in a country with a more adaptable accent, their vocabulary will remain with them, although their accent might not.
While I believe your language says a lot about you, I don’t necessarily believe that it defines you, more so it defines your upbringing, where, how and who you were brought up with. Although many others tend to judge people’s personalities based on their accent or language, all that does is, determine that people are their stereotypes, which they are not. People should be judged as individuals, not based on their language or any other physical features, as such.
