Unlike many other tests, the TOEFL isn’t designed to test your general English level, but rather your command of academic English. Some dialects of English are more similar to academic American English than others, so how difficult it is for you to learn academic English depends partly on the variety of general English that you know. If you’re learning everything from books and tapes (instead of being immersed and talking to native speakers), it can be really hard to distinguish between academic English and language that may be too informal to be appropriate. In this post, I’ll try to give you some guidance on how to speak at a level of formality (i.e. a register) that works on the TOEFL. I touched on this topic in a previous post about synonyms, but in this post I’ll go into more detail.
In almost all circumstances, written English is more formal than spoken English. We use a much broader vocabulary when writing than we do when speaking, and writing also tends to incorporate more complex sentence structures. If you try to speak in the same style in which you write academic papers, you will sound stilted—that is, so formal that you can’t communicate fully. The danger here is that you want to show off all of your fancy tricks—your most elaborate sentences, your most beautiful words—but that’s really not how people talk. Of course, you want to demonstrate that you have a high command of English, but the speaking section may not be the place for it. Instead, use the writing section as your outlet for your most carefully-crafted, formal language.
On the speaking section, it’s best to focus on communicating your ideas clearly and using English as a native speaker might.