The document discusses several factors that influence how learners acquire knowledge of a second language (L2): 1) The social context, including the status of the first (L1) and second languages, impacts learners' attitudes and opportunities to learn L2. 2) Social experiences determine L2 quality and influence success. 3) Some L2s are harder to learn depending on the learner's L1, though the relationship between L1 and L2 is still undiscovered. 4) Both younger and older learners have advantages - younger have more brain plasticity while older have better analytical skills and pragmatics.