Hello Kike! I take it you are ESL speaker. (English as a second language). If that is the case, I can tell you, as an ESL speaker myself, that it is not too hard to learn the English vocabulary necessary to work in the call center company. I have worked on a couple of companies for more than 10 years now. You should receive complete training that usually goes from 2 weeks to a month depending on the company and the account or department you are going to work with.
For instance, if you are going to work in retail, you should expect to use common words such as: Expedite, logistics, and schedule. Acronyms like ETA (Estimated time of arrival) and many more that would become second nature very quickly.
Another interesting fact is that at some point, you will find very easy to understand most accents and jargon. If you work for USA, it is very common when you start to find it difficult to understand people from some states. In my case, I had some troubles with accents from Alabama, Boston and New York. Also from ESL speakers from India and China. Then again, practice is going to improve your ear and you will notice that it becomes a day by day thing.
Don´t overthink it. Just go find some tutorials on Youtube. There is plenty of videos and tutorials from every type of companies.
Good luck and here I am if you need anything else!!! :)