Learning English

I have been studying English for many years but I considerate that I'm not prepared to work in a Contact center or just hold a keep and conversation with a person from the United States or just that know English!
I feel that I have problems with vocabulary and listening and I just want to wanna prepare for my job interview job.

I'm studying sport training and I think of the possibilities if I learn to speak English, so I really want to learn English. If I has have made any errors please correct them. talk me about this.