If you’re a Professor Particular de Ingles (private English teacher) there are several reasons you will need to know the informal expressions as well as slang, especially if you are planning to apply for a job or put up a business that requires you to speak English.
First, corporate politics demand that you know how to understand the people around you, if you can’t communicate with employees or co-workers. Not everyone in the office or business environment will be speaking English formally. In fact, there are more people who tend to speak in conversational, relaxed tones than in the proper English grammar.
Second, you could learn a lot from your work environment if you understand slang, so if you’re unclear on this it may be a good idea to invest in a Curso de Ingles (English Course). Back room talk is just as influential as top floor management meetings. As a matter of fact, by talking to people who work with you or under you, you can get a lot of inside information that you may find useful.
Third, if you understand and can speak the lingo of the common worker, then you will have an easier time being accepted as one of the guys. No one likes being talked down to, and if you can’t blend in and stick to formal English as your main means of communication, you may not make friends easily.
The fourth reason why you should learn the local slang is because if you plan to get involved in the retail business where you have to face customers and clients, then you should be ready and able to communicate as a front liner. This is the person who sells, talks to customers about their complaints or issues, and helps them with their needs as far as the business is concerned. You should expect to meet different people from all sorts of different environments and background.
What you need to make sure is that you understand the meaning of each slang expression you use, because you could get into a lot of trouble if you use outdated or politically incorrect words. You can find out what these are by going on the internet and using a search engine to find out potentially troublesome phrases.
Also, don’t depend on some stranger to teach you slang words or expressions because it could backfire on you if they play a joke on you. However, if you are willing to go along with the joke for the sake of being able to fit in, then be sure to make amends right away if you end up offending someone.
You should also realize that slang in one community may be considered offensive in another neighborhood halfway across the country. If you are planning to migrate to an English-speaking country, or be around native English speakers, then be sure you know which part of the country they come from. The English have different expressions from the Americans, and the same is true with the Canadians and Australians. Thus, be careful about which slang expression you use.
In the same manner, each business environment will have its own specific slang expressions. For instance, the computer industry has its own expressions and even vocabulary, as with the banking and finance sectors. It would be wise to stick to learning the casual expressions used in the business you are planning to enter into.