First-language speaker
Someone who acquired the language as a mother tongue in childhood, rather than learning it later.
UNESCO’s grades turn on this distinction. A language is definitively endangered when it “is no longer being learned as the mother tongue by children in the home”; it is unsafe when most children “speak their language as their first language”. Glottolog counts spoken L1 languages on the same basis — those “traditionally used by a community of speakers as their first language”.
The category is doing real work, but its edges are softer than the labels suggest. Childhood acquisition varies in completeness; people who were spoken to but not answered in a language occupy an uneasy middle; and in a shrinking community the question of who counts can become a question about belonging.
Where a profile here says first-language elder it means someone who grew up in the language. Where it says learner or new speaker, it does not — and the distinction is deliberate, because conflating the two overstates how much is left.