In my opinion, yes. Fluency in a language is comprehension and production. What you wrote above was production of (very) fluent English, which was in turn evide

In my opinion, yes. Fluency in a language is comprehension and production. What you wrote above was production of (very) fluent English, which was in turn evidence of good comprehension of the linked article. Fluency in another language implies the ability to dwell ‘naturally’ in the language, and I don't think that your dwelling mostly in the written form of the language would lessen the benefits that this paper suggests bilingualism can bring.