Note: I'm not a linguist, and I realize I might be treading in a grey area here.
I'm wondering what the differences (and/or similarities) between native language, first language, mother tongue and L1 are. The first three, I find, are often used interchangeably in casual conversation. In academic linguistics though, are there generally accepted differences between these terms? Also, where does that leave L1? I believe it's an academic term, but I often see it defined relative to the other three casual terms.
A quick Google search seems to reveal there is a lot of confusion around these terms, and possibly no straightforward answer. It also doesn't help that the Wikipedia article groups the four terms into one article and has fewer citations than I would like. The only thing I've been able to gather is that the tendency seems to be for "native language" to mean proficient and for "first language" to mean chronologically first.
In particular, I'd like to find out (if possible) what term or terms are applicable to the following scenarios:
- A chronologically first language with which the speaker is no longer fluent or even competent.
- A language learned to fluency in adulthood (with or without a foreign accent - though I realize the latter is rare).
- A language learned to fluency in childhood (within the critical period) that is not chronologically first.
I realize fluency might not be the best word to use...but the words I would normally use are the ones that I'm seeking clearer definitions for!