‘Perhaps because of the use of = for assignment in FORTRAN […] assignment is often read as “x equals E“. This causes great confusion. The first author learned to distinguish between = and := while giving a lecture in Marktoberdorf, Germany, in 1975. At one point, he wrote “:=” on the board but pronounced it “equals”. Immediately, the voice of Edsger W. Dijkstra boomed from the back of the room: “becomes!”. After a disconcerted pause, the first author said, “Thank you; if I make the same mistake again, please let me know.”, and went on. Once more during the lecture the mistake was made, followed by a booming “becomes” and a “Thank you”. The first author has never made that mistake again! The second author, having received his undergraduate education at Cornell, has never experienced this difficulty.’
– David Gries and Fred B. Schneider (1993, p. 17, footnote 6) [A logical approach to discrete math. Springer.]
R lets you use both = and <- for assignment, FYI.