Top-down processing of language happens when someone uses background information to predict the meaning of language they are going to listen to or read. Rather than relying first on the actual words or sounds (bottom up), they develop expectations about what they will hear or read, and confirm or reject these as they listen or read. Top-down processing is thought to be an effective way of processing language; it makes the most of what the person brings to the situation.
Asking learners to predict what a newspaper article might be about from the headline or first sentence will encourage them to use top-down processing on the article.
In the classroom
Learners can be encouraged to use both bottom-up and top-down strategies to help them understand a text. For example in a reading comprehension learners use their knowledge of the genre to predict what will be in the text (top down), and their understanding of affixation to guess meaning (bottom up).