1. A computer-implemented method comprising: obtaining a lexicon model that maps phones to spoken text; obtaining a language model that assigns probabilities to written text; generating a transducer that maps the written text to the spoken text, the transducer mapping multiple items of written text to an item of the spoken text; and constructing a decoding network for transcribing utterances into written text, by composing the lexicon model, the inverse of the transducer, and the language model.