I see no reason why the ability to write English well should have any effect on one's ability to speak the language well.
Edited: Title; Does writing ability help improving speaking ability for English learners?Is it true that writing ability helps improving speaking ability for English learners and why?
However, ... we've been ... writing for an average of merely 2000 years).
Very similar to my experience of learning French in the 1950s and 60s. When I graduated (English and French), I could write academic essays on Corneille, Racine, etc, translate fairly abstruse texts from English to French and vice versa, and discuss (in English) arcane points of French grammar. None of this helped much when I went to France. I couldn't understand the strange language the French actually spoke, and they were most amused by the pompous, unnatural words I uttered.In my teaching I have come across many older French learners of English who could read and write perfect English but were very poor at speaking.
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