Español y El Cerebro
Learning a Second Language
Young learners learn faster then older learners because of a few key reasons. One is because they learn the language in one spot in their brain, whilist older people learn in multiple spots of their brain. Before laterlization (puberty) is the best time to learn because the brain is still soaking up knowledge and not going through the changes in the brain. Also, if you learn before the age of 5, you're considered a native speaker In both languages and more likely to develope a native accent.
The advantages of learning when you're older is you can constantly use strategies to aid you're learning and you could draw knowledge from the language you already know to help with the second. You would also have greater control over your input.
To be profiencent you'd need to accel grammically, socialinguistic, discourse and strategic competense. For BICS (Basic Interpersonal Communication Skills) it would take 2-3 years. For the ability to read, write, speak and listen, it would take 4-10 years. It all depends on your drive, and if people around you speak the same language. If they do, it's a lot faster.