A learning plateau is a term that is often used in educational psychology. This is a kind of phenomenon that refers to a situation when the learner in the course of learning, despite all the efforts of learning and practice, seems to make no significant progress. In the beginning of the process, the learning curve is steep, then it gradually starts leveling out. The learning plateau is that flat part of learning curve which comes after rapid progress initially. However, after being in plateau for certain period, the learner will continue to make progress.
The plateau period is sometimes also referred as the "Temporary Fossilization," which is a prelude to permanent fossilization. Fossilization means the rules and linguistic items of the native language of the speaker persist in the inter-language relative to a target language. When compared to fossilization, the plateau is the temporary and reversible stage of language learning.