All the Latin letters, except for G, which is a modified Greek letter invented by a Roman, come from the Greek alphabet, only at different times. The original

All the Latin letters, except for G, which is a modified Greek letter invented by a Roman, come from the Greek alphabet, only at different times. The original Latin alphabet had 21 letters: ABCDE FZHIK LMNOP QRSTV X The letter V (Greek u-psilon) was used to write the sound U, both as vowel and as consonant (i.e. like English W). The letter F (Greek di-gamma) was used in Greek for consonant U (English W), but in Latin it was used to write the sound F, also a labial consonant, which did not exist in Greek. In Latin, in the beginning 3 different letters were used to write the sound K, C before E or I, K before A and Q before O or U. So K belonged to the Latin alphabet since its very beginning. Later, the rules for writing K have been simplified, so it was always written as C, except before a V (i.e. U sound) that was consonant, not vowel, i.e. like English W. Writing K has been retained only in a few traditional expressions, e.g. in "KALENDAE", which was used when writing dates. Initially, the letter C (Greek gamma) was used both for the sound K and for the sound G. Later, the letter G has been created, by modifying the letter C. Since then, G was used for the sound G, except in a few traditional expressions, e.g. the name "Gaius" has continued to be written as "Caius", together with a few other traditional names. The new letter G has substituted in the Latin alphabet the letter Z (Greek zeta), which was not used in Latin. Therefore the 21-letter Latin alphabet has become: ABCDE FGHIK LMNOP QRSTV X Several centuries later, during the Roman Empire, 2 additional Greek letters have been added at the end of the alphabet, so the 23-letter Latin alphabet was: ABCDE FGHIK LMNOP QRSTV XYZ The letter Z was reintroduced, but not in its original place, because it was contained in some borrowed Greek words. The same with Y. While both V and Y come from Greek u-psilon, by the time when Y has been added to the Latin alphabet it was pronounced as a vowel different from both Latin V and I, i.e. as a front rounded closed vowel, like the Scandinavian Y, German Ü (U with Umlaut) or French U. The 23-letter Latin alphabet has become a 26-letter alphabet more than a millennium later, when the letters J, U and W have been added (J and U were required because in the Romance languages the old I consonant and U consonant had become fricative sounds, completely distinct from the I and U vowels, while W has been initially added for English, which is one of the few Indo-European languages that has retained the original pronunciation of consonant U).