I have to come clean about something: English language schools have been selling business English for a long time. But "Business English" is not real.
First, let’s answer a simple question. What is English? It’s a language. It’s words and phrases linked with grammar and syntax. There are rules about writing. There are rules about pronunciation.
Is there business pronunciation? No. All pronunciation can be used in business situations.
What about grammar? It's, of course, the same. Different business situations require all kinds of grammar.
All English is business English.
What about vocabulary? Most communication uses the same basic words. But there are specialised words for a certain industry. If you work in sales, you might need to know about sales targets, or quarterly reports, or trends. If you work in the energy industry, you might need to talk about photovoltaic solar energy.
So we see general vocabulary and industry vocabulary.
Some workplaces use certain words or phrases. You might meet a “tight deadline” or send a “quick email.” But you can find such common phrases outside the workplace, too.
Some learners think business English is formal. But if you have worked in an English-speaking office, you know it's often casual. In fact, if you are too formal with a client who is speaking casually, you will be mismatched and possibly seem rude.
Some learners think everyday English is not polite or formal. But if you have ever ordered food at a restaurant, you have used formal English. We say, “Could I get a hamburger, please?” And, to catch the waiter’s attention, “Sorry, would you mind if I get a glass of water? Thanks.” Formal, polite English often happens outside the office.
Many students use the Business Result textbooks. That’s a fine choice, so long as it’s not boring or too difficult. The Business Result course gives you a good starting place. But it does not cover all the English you need to do business. It probably doesn't focus on your industry. Successful business people learn English from many places.
If you learn English by watching exciting TV shows or listening to interesting podcasts, you will be able to use that English to do business. Of course, the use depends on context. Some situations need formal language, others need casual language. But all English you study is useful for doing business in English.