1. A computer program product for generating a code alphabet for use by a deployed program to determine codewords for words used in a computing system, wherein the codewords have an average codeword length less than a length of the words, the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that executes to perform operations, the operations comprising: providing a first code alphabet having a first number of symbols that provide variable length codings of the words; and generating a second code alphabet having a second number of symbols formed by merging the symbols in the first code alphabet, wherein the second code alphabet comprises the code alphabet used by the deployed program.
2. The computer program product of claim 1 , wherein the operations further comprise: generating a word frequency distribution of frequencies of occurrences of all of the possible words; assigning values to different numbers of groups of merged words based on the word frequency distribution; and selecting one of the numbers of the merged words based on the assigned values, wherein the first number of symbols comprises the selected number of the merged words, wherein each symbol maps to one of the merged words.