J split off from I in the sixteenth century. G was invented by a named Roman schoolmaster. Z was thrown out of Latin and let back in at the end.
F — F, U, V, W and Y all descend from one Phoenician letter, waw. Five letters of the English alphabet are the same ancestor, split five ways. more
G — one of the very few letters with a name attached to it. The tradition, from Plutarch, credits a Roman schoolmaster, Spurius Carvilius Ruga, with adding a stroke to C to separate [g] from [k]; the new letter took the slot Z had vacated. Scholars argue whether he invented it or standardised a split already under way — the date is traditional, not documented. more
J — the youngest letter of the alphabet. The Italian Gian Giorgio Trissino argued in 1524 that I was doing two jobs, and English took another century to agree. Shakespeare's first editions print I where we write J: Iulius, Iohn. more
Q — Greek eventually dropped this letter and kept it only as a numeral — but Latin had already taken it, through Etruscan, while it was still in use. Latin gave it one job, the combination QU, and English keeps it: outside borrowed words like Qatar and burqa, a q here is followed by a u. more
U — for most of its life U and V were one letter with two shapes, chosen by position rather than sound: V at the start of a word, U inside it. The split into a vowel and a consonant is younger than printing. more
W — the name says what it is: double u. Old English wrote this sound with a rune, wynn, and scribes on the continent wrote it uu; the ligatured form came into English with the Normans and took two centuries to push the rune out. more
Y — French still calls it i grec, "the Greek i". Latin brought it in specifically to spell borrowed Greek words and never fully naturalised it. more
Z — Latin threw Z out around 300 BC as useless, and G was created to take its empty slot. Centuries later Greek loanwords made it necessary again, so it was let back in — at the end, where there was room. That is why the alphabet finishes on it. more