Written English uses many abbreviations. Poligo has a list of formal abbreviations that are often used in business emails, notes and memos.

This list will help you understand casual English abbreviations. These are often used on the web or in SMS messages and emails between friends. The written examples are all casual English. This way of writing is very informal, and some people think it is very bad. Use these kinds of abbreviations very carefully. Don't use them in business emails or with people you don't know very well. You'll make a bad impression.

In informal English (spoken and written), it is sometimes possible to drop the subject from your sentence. Generally speaking, you can only do this if both of these two things are true:

1. the word you drop is a pronoun; and
2. it is the first word in the sentence.

Compare these two sentences:

1. I went for a drink with a friend from work; and
2. Went for a drink with a friend from work.