For speech recognition with large vocabularies, a user should not be burdened with having to train several thousand words explicitly. Therefore, it proves extremely useful to provide a means for easy vocabulary generation and enlargement from written text input. Applying a set of appropriately defined rules, the orthography of a lexicon item is first transcribed into the phonetic symbols of the standard pronunciation and the most common alternatives thereof. From these, the multiple sequence of specific subword units of a lexicon entry is produced. The tool introduced here is part of a comprehensive speech processing system for subword-unit based, speaker-adaptive recognition of continuous speech.