This gives them a reason to listen or read, as they confirm or reject their predictions.
Example
Learners are going to listen to a presentation about a journey through Africa. They predict what vocabulary they might hear, and also what kind of emotions the speaker might have felt. They listen to confirm their ideas.
In the classroom
Prediction is a valuable stage in listening and reading activities. It mirrors L1 skills use, where predictions form an important base for being able to process language in real time. Both content and language can be predicted.
Further links:
https://www.teachingenglish.org.uk/article/techniques-priming-recycling
https://www.teachingenglish.org.uk/article/pause-predict-%E2%80%93-youtube-technique
https://www.teachingenglish.org.uk/article/predicting-language-context
https://www.teachingenglish.org.uk/article/using-news-articles
https://www.teachingenglish.org.uk/article/my-wikipedia
https://www.teachingenglish.org.uk/article/storytelling-carnival-crime