speech synthesis

In many modern applications such as directory assistance, name dialing, car navigation, etc. one needs a speech recognizer and/or a speech synthesizer. The former to recognize spoken user commands and the latter to pronounce information found in a database. Both components make use of phonetic transcriptions of the words to recognize/pronounce. In order to develop an application, the developer needs a tool that accepts words/sentences and that returns the phonetic transcriptions of these words/sentences.