This document discusses L2 learning and teaching. It defines L2 as any language learned after one's first language. There is disagreement about whether L2 knowledge consists of underlying rules, linguistic patterns/structures, or a means of communication. Learners acquire L2 through innate capacity, prior knowledge, processing input, interaction, restructuring knowledge, and automatization. Success varies due to social context, experience, the relationship between L1 and L2, age, aptitude, motivation, and instruction quality. Near-native competence is unlikely in pronunciation for older learners and requires extensive varied input and feedback. Implications include considering learners' goals, priorities, dimensions of learning, strengths/limitations, and incremental progress