Some teaching methods typically give learners the opportunity to learn only a restricted number of words and sentence types. Even when the language teaching method provides much richer language input, the fact that something is taught or made available in the input does not mean learners will acquire it right away. For example, some aspects of the second language emerge andevolve according to developmental sequences, and learners may be more likely to learn certain language features when they are developmentally ready. Thus, attempts to teach aspects of language that are too far away from the learner's current stage of development can be frustrating. Other language features, for example, vocabulary, can be taught at any time, as long as the learners are interested in the opportunity to learn and the teaching methods are appropriate to the learner's age, interests, needs, experiences, and learning styles.