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
Morse code mnemonics the elements of the Morse code characters onto pictures for easy memorization. For instance, "R" () might be represented as a "racecar" seen in a profile view, with the two wheels of the racecar being the dits and the body being the dah. Syllabic mnemonics are based on the principle of associating a word "or" phrase to each Morse code letter, with stressed syllables standing for a dah and unstressed ones for a dit. There is no well-known complete set of syllabic mnemonics for English, but various mnemonics do exist for individual letters. In the Czech language, the mnemonic device