What's the difference between i.e. and e.g.?
late 14c., from Old French especial "pre-eminent, important," from Latin specialis "belonging to a particular kind or species," from species "kind" (see species).
Latin words with initial sp-, st-, sc- usually acquired an e- when borrowed by Old French. Modern French has restored the word to spécial. Originally with the same sense as special, later restricted to feelings, qualities, etc.