Abstract: Character string recognition and identification is accomplished with a combined, multi-phase top-down and bottom-up process. Characters in an applied signal are recognized with a process that employs a knowledge source which contains information both, about the basic elements in the signal and about strings of the basic elements in the signal. The knowledge source, which may be derived from a training corpus, includes word probabilities, word di-gram probabilities, statisitics that relate the likelihood of words with particular character prefixes, and rewrite suggestions and their costs. Higher level word n-grams, such as word tri-gram probabilities, can also be used. A mechanism is provided for accepting words that are not found in the knowledge base, as well as for rewrite suggestions that are not in the knowledge base.