1 Answer

The letter K comes from the letter Κ (kappa), which was taken from the Semitic kap, the symbol for an open hand.[2] This, in turn, was likely adapted by Semites who had lived in Egypt from the hieroglyph for "hand" representing D in the Egyptian word for hand, d-r-t. The Semites evidently assigned it the sound value /k/ instead, because their word for hand started with that sound.[3] In modern-day English slang, the word "k" is used as a substitute for the abbreviation "O.K.", or "Okay." In International Morse code it is used to mean "over".[4]

In the earliest Latin inscriptions, the letters C, K and Q were all used to represent the sounds /k/ and /g/ (which were not differentiated in writing). Of these, Q was used to represent /k/ or /g/ before a rounded vowel, K before /a/, and C elsewhere. Later, the use of C (and its variant G) replaced most usages of K and Q. K survived only in a few fossilized forms such as Kalendae, "the calends".[5]

When Greek words were taken into Latin, the Kappa was changed to C, with a few exceptions such as the praenomen Kaeso.[2] Some words from other alphabets were also transliterated into C. Hence, the Romance languages have K only in words from other language groups. The Celtic languages also chose C over K, and this influence carried over into Old English. Today, English is the only Germanic language to productively use hard C in addition to K (though Dutch use it in learned words of Latin origin and follows the same "hard / soft" distinction in such words as does French and English – but not in native words).

http://en.wikipedia.org/wiki/K