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Phonetics Laboratory
Faculty of Linguistics, Philology, and Phonetics

assa and ipox image


IPOX is an all-prosodic speech synthesizer, based in part on YorkTalk (Coleman 1992, Local 1994), currently being developed by Arthur Dirksen at IPO and John Coleman at Oxford University.

All-prosodic means:

  • no principled distinction between segmental and supra-segmental prosodic structure
  • speech generated directly from prosodic structure


  • declarative, no rewriting rules
  • analysis of input using constraint-based grammars
  • compositional phonetic interpretation
  • metrical structure (prosodic headedness) used in both analysis and phonetic interpretation
  • fully integrated system, including formant synthesis and speech output


  • further formalize and extend the YorkTalk architecture
  • develop a multi-lingual version
  • make the YorkTalk model accessible to phonologists and speech researchers

Current capabilities (British English):

These demo's were played at the Second ESCA/IEEE Workshop on Speech Synthesis (September 1994), Dirksen and Coleman 1994.

Arthur Dirksen / adirksen@prl.philips.nl / January 1995