Avoid formal language
In the IELTS speaking test, many candidates believe that they will impress the examiner by using very formal vocabulary. In fact, the speaking test is supposed to represent everyday 'educated' speech -- not highly formal, but at the same time you should not use language that is too informal, such as slang. In the table below, I include some examples of overly formal words and phrases that you should try to avoid in the speaking test.