Acquisition is the way we learn our first language, i.e. through being involved in real communication, and without formal teaching. As we learn, we hypothesise rules, and use these to communicate until we notice that the rule is different, or has exceptions. This leads to classic early mistakes such 'I seed' and 'I buyed'. Language learning programmes that immerse learners in the target language aim to create the conditions for acquisition to happen in second language learning. In a communicative classroom, opportunities for natural acquisition are often provided alongside opportunities for formal learning, to make the most of both ways of learning.