In an oral history interview with Philip Frana in 2001, Edsger Dijkstra talks about the importance of articulateness in natural language:
There is an enormous difference between one who is monolingual and someone who at least knows a second language well, because it makes you much more conscious about the phenomenon of language structure in general. You will discover that certain constructions in one language you just can’t translate. I was once asked what were the most vital assets of a competent programmer, and I said, at the time, a mathematical inclination and an exceptional mastery of his native tongue. I said “mathematical inclination” because at the time it was not clear how mathematics as understood at that moment could contribute to a programming challenge. And I said “native tongue” and not “English” because, well for lack of formalism, you have to think in terms of words and sentences using a language you are familiar with. Moreover, but I didn’t know that at the time, research has shown that when people acquire a second language, they never get a greater mastery of it than they have of their own language, their native tongue: that clearly sets the standard for how articulate you are going to be.
Edsger W. Dijkstra, OH 330. Oral history interview by Philip L. Frana, 2 August 2001, Austin, Texas. Charles Babbage Institute, University of Minnesota, Minneapolis. P. 9 of PDF.