For those who think we have no dual in English, note “either”, “each of two”, from
“…Old English aegther (before 900), contraction of aeghwaether each of two, both (a – always, + ge- collective prefix + hwaether which of two, WHETHER). English either is cognate with German jeder each (originally of two). About 1290 either assumed the sense of one or the other of two, which has prevailed in modern English.”
– The Barnhart Concise Dictionary of Etymology