There are many reasons for learning English. What I'm getting is that some learners may need to put business plans and hold about different subjects, while others from the same companies may just need to take messages over the phone, put faxes and make short letters.
Teachers of general English assume that learners will want to put their basic requirements, get personal information, put their preferences and opinions and take certain topics in conversation or debate.
Teaching languages often involves passing social skills such as cutting other speakers. I bring this because in some countries it is considered rude. By laying what English people do, we are teaching the culture. Learners often look their teachers for information about English habits. For example, how do English people address their bosses when putting a pay rise? Teachers have to be very careful because their language and behaviour are held examples of how English is spoken and what English people do. If the same learners turn another teacher for similar advice, the answers may be different!