1. A computer program product comprising: a computer usable medium having computer readable program code embodied therein configured to adapt a language unit, the computer program product comprising: computer readable code configured to cause a computer to calculate a mutual information value between a first chunk and a second chunk; and computer readable code configured to cause the computer to add a new word to the language unit when a condition involving the mutual information value is satisfied, the new word being a combination of the first chunk and the second chunk, wherein computer readable code configured to cause the computer to add the new word includes: computer readable code configured to cause the computer to add the new word into an n-gram store, the n-gram store including a plurality of n-grams and associated frequency or count information; and computer readable code configured to cause the computer to alter the frequency or count information based on the new word.