3-5 years for the first language to a general level of fluency. The impressive part is that they can generally pick up fluency in a second language in a year with minimal instruction, and they can learn multiple at the same time.
Unless it's the only thing you're doing, you're not going to be fluent in a second language as an adult after a year of study.
On a chemical level, children's brains work differently to adults when they're learning, it's not a question of effort.
3-5 years for the first language to a general level of fluency. The impressive part is that they can generally pick up fluency in a second language in a year with minimal instruction, and they can learn multiple at the same time.
Unless it's the only thing you're doing, you're not going to be fluent in a second language as an adult after a year of study.
On a chemical level, children's brains work differently to adults when they're learning, it's not a question of effort.