1. A computer-readable medium having stored thereon a first lexicon data structure for each of a plurality of lexicon words, the first lexicon data structure comprising: a host form variant field containing data representing a host form variant; a host form word field containing data representing a host form word for the host form variant represented by the data of the host form variant field; and a verification field containing data representing a property of the host form variant represented by the data of the host form variant field, the property being indicative of whether the host form variant is itself a valid word or whether the host form variant must be combined with another entry in the lexicon.