Eleventh letter of the Latin alphabet
K, or k, is the eleventh letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is kay (pronounced ), plural kays.[1] The letter K usually represents the voiceless velar plosive.
History
The letter K comes from the Greek letter Κ (kappa), which was taken from the Semitic kaph, the symbol for an open hand.[2] This, in turn, was likely adapted by Semitic tribes who had lived in Egypt from the hieroglyph for "hand" representing /ḏ/ in the Egyptian word for hand, ⟨ḏ-r-t⟩ (likely pronounced /ˈcʼaːɾat/ in Old Egyptian). The Semites evidently assigned it the sound value /k/ instead, because their word for hand started with that sound.[3]
K was brought into the Latin alphabet with the name ka /kaː/ to differentiate it from C, named ce (pronounced /keː/) and Q, named qu and pronounced /kuː/. In the earliest Latin inscriptions, the letters C, K and Q were all used to represent the sounds /k/ and /ɡ/ (which were not differentiated in writing). Of these, Q was used before a rounded vowel (e.g. ⟨EQO⟩ 'ego'), K before /a/ (e.g. ⟨KALENDIS⟩ 'calendis'), 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".[4]
After Greek words were taken into Latin, the Kappa was transliterated as a C. Loanwords from other alphabets with the sound /k/ were also transliterated with C. Hence, the Romance languages generally use C, in imitating Classical Latin's practice, and have K only in later loanwords from other language groups. The Celtic languages also tended to use C instead of K, and this influence carried over into Old English.
Pronunciation and use
English
English is now the only Germanic language to productively use "hard" ⟨c⟩ (outside the digraph ⟨ck⟩) rather than ⟨k⟩ (although Dutch uses it in loan words of Latin origin, and the pronunciation of these words follows the same hard/soft distinction as in English).[citation needed]
The letter ⟨k⟩ is silent at the start of an English word when it comes before the letter ⟨n⟩, as in the words "knight," "knife," "knot," "know," and "knee".
Like J, X, Q, and Z, the letter K is not used very frequently in English. It is the fifth least frequently used letter in the English language, with a frequency in words of about 0.8%.
Number
In the International System of Units (SI), the SI prefix for one thousand is kilo-, officially abbreviated as k: for example, prefixed to metre/meter or its abbreviation m, kilometre or km signifies a thousand metres. As such, people occasionally represent numbers in a non-standard notation by replacing the last three zeros of the general numeral with K, as in 30K for 30,000.
Other languages
In most languages where it is employed, this letter represents the sound /k/ (with or without aspiration) or some similar sound.
Other systems
The International Phonetic Alphabet uses ⟨k⟩ for the voiceless velar plosive.
