Yesterday my student and I were reading and discussing the memoir Black Boy by Richard Wright. In catching me up on what she'd read at home, she told me about an incident where some other boys were trying to incite the author to fight. She told me they "edged him on" where she meant "egged him on."
Wondering where this idiom originated, we decided to investigate the verb <egg> as in "urge" and were surprised to find this below on etymonline!
c.1200, from Old Norse eggja "to goad on, incite," from egg "edge" (see edge (n.)). The unrelated verb meaning "to pelt with (rotten) eggs" is from 1857, from egg (n.). Related:Egged; egging
Old English ecg "corner, edge, point," also "sword" (cf. ecgplega, literally "edge play,"ecghete, literally "edge hate," both used poetically for "battle"), from Proto-Germanic*agjo (cf. Old Frisian egg "edge;" Old Saxon eggia "point, edge;" Middle Dutch egghe, Dutch eg; Old Norse egg, see egg (v.); Old High German ecka, German Eck "corner"), from PIE root *ak- "sharp, pointed" (cf. Sanskrit asrih "edge," Latin acies, Greek akis"point;" see acrid).
Spelling development of Old English -cg to Middle English -gg to Modern English -dgerepresents a widespread shift in pronunciation. To get the edge on (someone) is U.S. colloquial, first recorded 1911. Edge city is from Joel Garreau's 1992 book of that name.Razor's edge as a perilous narrow path translates Greek epi xyrou akmes. To have (one's) teeth on edge is from late 14c., though "It is not quite clear what is the precise notion originally expressed in this phrase" [OED].
late 13c., "to give an edge to" (implied in past participle egged), from edge (n.). Meaning "to move edgeways (with the edge toward the spectator), advance slowly" is from 1620s, originally nautical. Meaning "to defeat by a narrow margin" is from 1953. The meaning "urge on, incite" (16c.) often must be a mistake for egg (v.). Related: Edged; edging.
My student has probably never see "egg him on" in print, so perhaps it's no coincidence that her own pronunciation alteration followed the historical shift from -cg to -gg to -dge described above. Interesting, too, that her use of <edge> to mean "incite" was attested in the 16th century, as possibly a mistake for <egg>.
It also surprised us that the verb <egg> "to incite" is attested long before the noun. I wonder if the spelling of the latter was influenced by the spelling of the former.