Low motivation, low self-esteem, and debilitating anxiety can combine to 'raise' the affective filter and form a 'mental block' that prevents comprehensible input from being used for acquisition. In other words, when the filter is 'up' it obstructs language acquisition.
The Affective Filter Hypothesis may be a useful tool to take into account in pronunciation practice in the classroom, especially when working with adolescents and adults. It could be highly beneficial for learners to create an atmosphere in which they feel comfortable and do not fear making mistakes. It is also important to consider that especially adults already have their affective schema and personality fully developed, so the instructor should only monitor the class in an attempt to lower the affective filter so the learners feel free to take advantage of the opportunity to practice their language, especially in listening comprehension and language production.
3.3 Accent and Cultural