1911 Encyclopædia Britannica/G
G The form of this letter which is familiar to us is an invention of the Romans, who had previously converted the third symbol of the alphabet into a representative of a k-sound (see C). Throughout the whole of Roman history C remained as the symbol for G in the abbreviations C and Cn. for the proper names Gaius and Gnaeus. According to Plutarch (Roman Questions, 54, 59) the symbol for G was invented by Spurius Carvilius Ruga about 293 B.C. This probably means that he was the first person to spell his cognomen RVGA instead of RVCA. G came to occupy the seventh place in the Roman alphabet which had earlier been taken by Z, because between 450 B.C. and 350 B.C. the z-sounds of Latin passed into r, names like Papisius and Fusius in that period becoming Papirius and Furius (see Z), so that the letter z had become superfluous. According to the late writer Martianus Capella z was removed from the alphabet by the censor Appius Claudius Caecus in 312 B.C. To Claudius the insertion of G into the alphabet is also sometimes ascribed.
In the earliest form the difference from C is very slight, the
lower lip of the crescent merely rising up in a straight line 
,
but 
and 
are found also in republican times. In the earliest
Roman inscription which was found in the Forum in 1899 the
form is 
written from right to left, but the hollow at the bottom
lip of the crescent is an accidental pit in the stone and not a
diacritical mark. The unvoiced sound in this inscription is
represented by K. The use of the new form was not firmly
established till after the middle of the 3rd century B.C.
In the Latin alphabet the sound was always the voiced stop (as in gig) in classical times. Later, before e, g passed into a sound like the English y, so that words begin indifferently with g or j; hence from the Lat. generum (accusative) and Ianuarium we have in Ital. genero and Gennajo, Fr. gendre and janvier. In the ancient Umbrian dialect g had made this change between vowels before the Christian era, the inhabitant of Iguvium (the modern Gubbio) being in the later form of his native speech Iuvins, Lat. Iguvinus. In most cases in Mid. Eng. also g passed into a y sound; hence the old prefix ge of the past participle appears only as y in yclept and the like. But ng and gg took a different course, the g becoming an affricate dẓ (dzh), as in singe, ridge, sedge, which in English before 1500 were senge, rigge, segge, and in Scotch are still pronounced sing, rig, seg. The affricate in words like gaol is of French origin (geôle), from a Late Lat. gabiola, out of caveola, a diminutive of the Lat. cavea.
The composite origin of English makes it impossible to lay down rules for the pronunciation of English g; thus there are in the language five words Gill, three of which have the g hard, while two have it soft: viz. (1) gill of a fish, (2) gill, a ravine, both of which are Norse, and (3) Gill, the surname, which is mostly Gaelic = White; and (4) gill a liquid measure, from O. Fr. gelle, Late Lat. gella in the same sense, and (5) Gill, a girl’s name, shortened from Gillian, Juliana (see Skeat’s Etymological Dictionary). No one of these words is of native origin; otherwise the initial g would have changed to y, as in Eng. yell from the O. Eng. gellan, giellan. (P. Gi.)