1. A method, comprising: tagging an input text string; examining, via a processor, the input text string for at least one first set of substitutions based on content of the input text string; and if the input text string is a substring of a previously tagged input text string: determining whether the input text string and at least one additional input text string share a common pre-assigned tag identifier stored in a memory location, and if the input text string and the at least one additional input text string share the common pre-assigned tag identifier stored in the memory location: eliminating at least one of the input text string and the at least one additional input text string from a natural language grammar.