Is the way we speak too entangled with our identity to change?

I feel that the way speak is too entangled with our identity to change because its part of who we are. If you talk a certain way it grows on. It may be hard to change your speech when you are so accustomed to talking that way. In certain situations we are sometimes forced to change the way we speak. For Example: If you want to get a job and go to the interview looking professional
they way that you normally speak(which might not be proper english) can jepordise your chances of getting a job that might require you speaking correctly. Different types of jobs require you to speak a different way of speeche. Some jobs require proper way of speeche and some do not.