Earlier quoted context omitted.
"Native speaker" is not a very useful term: it combines a lot of criteria (first acquired language, language you know best, language you identify with, language of your parents, language of your ethnic group etc.), and each of these criteria is further very fuzzy (e.g. I know plant names better in Ukrainian, but programming terms better in Russian, which language I know better? Competency is not a single value, ethni…
I grew up in southern Germany, speaking the local dialect. As a young adult, I thought I could speak accent free German. I couldn't have been more wrong. Many people in Hamburg and Berlin rightfully guessed that I'm from Bavaria. Closely related languages and dialects exist in a continuum ((Max Weinreich: "a language is a dialect with an army an a navy"). Many people in Ukraine spoke and speak "surzhyk", depending on…
I eventually managed to separate the languages proper but I clearly see how the languages are are not a discrete classification.
Like, lithuanian polish and lithuanian russian are similar, but polish polish is further away phonetically.
Lithuanian has weird phonetics but the underlying grammar is very close to slavic languages.
English is much further away on the spectrum but why are sentence intonations (irony , question, etc) are still strangely compatible with languages from other branches of the language tree..?
Conclusion: strict language separation is a political construct not a natural thing.