Can passive speakers of a language gain native level fluency when learning it in their teens?

Question

Many immigrant kids grow up understanding a language fluently, but unable to speak it. This is known as being a passive speaker, as far as I know.

If they decide later to actively begin learning to speak the language they understand, will they be able to become as fluent as a native speaker? Presumably they have some advantage over those who don't know the language in any way at all.

I'm also interested in whether or not they can have a native level pronunciation of their language when actively speaking it, apart from grammar.

I'm particularly interested in whether or not a teenager (14-17) who had a strong interest in their language would be able to achieve this, since it is well known that older learners cannot learn a new language as well as a younger person could.

Answer 1

There is no reason to think that a Passive Bilingual/Speaker can't become a fluent speaker. In fact, they should have an easier time than someone who is learning the language from scratch.

The main issue the person will have to overcome, and this could be a mental block, is actively using the language. They are so used to just listening and comprehending and will need to develop new habits. If such a person were to move to an immersive environment where they have no choice but to speak that language, then they would "unlock" their mouths pretty quickly, especially compared to someone who is a beginner.

As for sounding like a native speaker - it's possible. That will be hard, since they will likely have the accent of their active language at first. However, the person presumably has heard the passive language their whole life, so they have a chance to attain a native accent if they work very hard and train their mouths properly. I looked but do not see any academic articles on this exact topic.

Age 14-17 is still pretty young. I know someone who moved to another country at age 11 and learned a completely different language, yet achieved native-level fluency (including accent). Someone who is 14 and has heard the passive language their whole life has an advantage, in my opinion, over the person I know. As long as they are immersed and try for a native accent (note: I know that some people work harder than others at this), then they can do it.