What are the limits on grammar size?
Though the speech recognizer doesn’t place a specific limit on grammar size, several practical considerations serve to effectively limit the maximum grammar size to tens of thousands of entries. First, as the grammar grows in size, the recognizer must test an utterance against a larger number of possibilities, slowing the recognizer considerably. Second, the larger the grammar, the greater the possibility that it contains words that are easily confusable. This lowers the accuracy of the grammar. However, with careful planning, it is possible to create large grammars that are still effective. Tellme has production grammars with up to thirty thousand entries.
