1. A method of extracting new words automatically, said method comprising the steps of: segmenting a cleaned corpus in a domain to form a segmented corpus; splitting the segmented corpus to form sub strings, and counting the occurrences of each sub string appearing in the corpus; and filtering out false candidates to output new words, wherein the new words are words not contained in a base vocabulary; wherein the segmenting and the splitting is not dependent upon word boundaries; wherein new words are determined based upon the domain of the cleaned corpus; wherein the step of splitting and counting is implemented using a GAST (general atom suffix tree) contained in a reduced memory space; wherein the GAST is implemented by limiting length of character sub strings.