What are the realistic/optimal (or maximal) number of words of vocabulary that can be learned (retained and later successfully accessed) by an adult learner of a foreign/second language? (Unit: per day, week, or year.)Initial research:Read the Wikipedia article - result: Only focuses on children and their native language acquisition (as many articles do) vs. adults, who train conscientiously!Google search: Which search terms would you recommend? Results from vocabulary acquisition and amount of words/vocabulary (+daily) are in review.I did not find much yet, see below..Google Scholar: In progress... (vocabulary acquisition and adult vocabulary acquisition speed)Unverified statements found from Google search:I am a student at the Defense Language Institute. We are required to learn about 80 words a day. (Source) - I tried to access the DLI / DLIFLC website to verify this, but the website was down yesterday (31.08.2012, 1:30 am, GMT+9)
What is the average amount of new vocabulary adults retain when learning a second language?
memory;learning;language