In the monitor model, linguist Stephen Krashen proposes that language learning is accomplished either through learning (formal, conscious learning about language) or through acquisition (informal, subconscious learning through experience with language). He suggests that there is an internal "monitor," which is developed through formal learning which is a part of the conscious process of error correction in when speaking a new language. The monitor plays only a minor role in developing fluency, compared to the role of acquisition. This model later became part of Krashen and Terrell's Natural Approach to language teaching (Krashen & Terrell, 1983).