Letter frequency xz. Modern International Morse code (generally believed to have been developed by Alfred Vail based on English-language letter frequencies of the 1830s) encodes the most frequent letters with the shortest symbols; arranging the Morse alphabet into groups of letters that require equal amounts of time to transmit, and then sorting these groups in increasing order, yields e it san hurdm wgvlfbk opxcz jyq. Similar ideas are used in modern data-compression techniques such as Huffman coding. Letter frequency was used by other telegraph systems, such as the Murray Code. Letter frequencies, like word frequencies, tend to vary, both by writer and
Letter (alphabet) letters have prescribed orders, although this too may vary by language. In Spanish, for instance, "ñ" is a separate letter, sorted after "n". In English, "n" and "ñ" are classified alike. As symbols that indicate segmental speech, letters are associated with phonetics. In a purely phonemic alphabet, a single phoneme is denoted by a single letter, although in history and in practice letters often indicate more than one phoneme. There are more sounds, or phonemes, in English–about 44–than there are letters of the alphabet. A letter may therefore be associated with more than one phoneme, with the phoneme determined by