According to wikipediaBusiness English is English language especially related to international trade. It is a part of English for Specific Purposes and can be considered a specialism within English language learning and teaching; for example, the teachers’ organization IATEFL has a special interest group called BESIG. Many non-native English speakers study the subject with the goal of doing business with English-speaking countries, or with companies located outside the Anglosphere but which nonetheless use English as a shared language or lingua franca. Much of the English communication that takes place within business circles all over the world occurs between non-native speakers. In cases such as these, the object of the exercise is efficient and effective communication. The strict rules of grammar are in such cases sometimes ignored, when, for example, a stressed negotiator’s only goal is to reach an agreement as quickly as possible.

And these are some of types of english letter:
1. Informal Letter Writing
These types of letter are written to relative or friends. These can also include invitations, etc. Such kinds of letter are also known as Personal or Social Letters.

2. Business Letter Writing
These letters are used as a communicative tool in the business and are usually written by the traders, firm and companies etc for business purpose. These kinds of letter fall under the category of formal letters.

3. Official Letter Writing
These include letter of application, letter to government officials and letter to newspaper etc. These letters are used for the official communication of the information from one department to another. Example; Termination letter, Recommendation letter, Reference letter, Job letter etc.

Parts of Letter:
1. Heading
2. The Salutation or Gorgeous Greetings
3. The Body
4. The Subscription
5. The Signature
6. The Address

Styles of Business Letter:
1. Full Block Styles
2. Block Styles
3. Semi Block Styles
4. Idented Styles
5. Simplified
6. Hanging Idented Styles