Conclusion

It seems to me that the way a character talks does partly show what kind of a character they are, but it is not the most important thing. It is easier to see a personality from how the character acts or how others react to him or her. Of the characters that can be easily identified due to their ways of speaking, villains are the easiest. The way that characters talk can help determine what kind of a movie it is (action movies will generally have a lot of cursing and snappy talking, while stoner movies will just have a lot of cursing). However, there are many more factors, such as the plot (obviously), the setting and the characters in general. That last one can be argued because the character can be judged by how they talk, but as I said, the way of speaking is not the most important factor. On the other hand, people do tend to judge characters by their voices and ways of talking, just as they do real people.