PLS for SSML

Paolo BaggiaLoquendo

Workshop II on Internationalizing SSML

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Outline

• Brief Introduction of Pronunciation Lexicon Specification

• Examples of common use cases

• How to deal of Homographs in PLS

• Other issues for the workshop

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Why Pronunciation Lexicon Specification?

• Allow to customize pronunciations (for proper names, locations, addresses, acronyms, etc.)

• Enrich TTS and ASR with customized pronunciations

• Complete the “Speech Interaction Framework”

Read the specification at:http://www.w3.org/TR/pronunciation-lexicon/

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What PLS 1.0 is Not!

• Multilingual pronunciation lexicon the current specification is mono-lingual!

• Extended purpose lexicon no syntax, no semantics, no morphology

• TTS-internal lexicon too complex and rich of custom knowledge

PLS 1.0 is restricted to the most important and tractable issues.

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The PLS 1.0 Language

• PLS is an XML language <?xml version="1.0" encoding="UTF-8"?>

• The root element is <lexicon>,

with attributes version, xmlns, alphabet, xml:lang

• It contains a collection <lexeme>s, which is composed of:

– <grapheme>s for orthographies/spellings

– <phoneme>s for pronunciations

– <alias>s for textual substitutions

– <example>s for examples

The order is relevant to determine the preferred pronunciation for

TTS

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PLS Common Usages

• Multiple pronunciations

– For ASR: to accommodate speaker/regional variability, not native

speakers

– For TTS: a single preferred pronunciation will be selected

• Multiple orthographies (with same pronunciations)

– For ASR & TTS:

• Homophones (same pronunciations, different meanings)

– Different <lexeme>s

• Homographs (same spellings, different pronunciations)

– This creates troubles we propose a solution

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How to Deal with Homographs

• New attribute “role” on <lexeme> elements

<lexeme role=“value”/>

• Values are qnames (qualified names, with a namespace)

e.g. “myvocabulary:verb”, “wordnet:verb”

• Open to future standardization

allows both proprietary values and standard ones

• More than one qname for a single <lexeme>,

e.g. role=“w:verb w:past-tense”

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Example of Homographs in PLS

<?xml version="1.0" encoding="UTF-8"?><lexicon version="1.0" xmlns="http://www.w3.org/2005/pronunciation-lexicon" alphabet="ipa" xml:lang="en-GB"> <lexeme role="wdn:verb"> <grapheme>refuse</grapheme>

<phoneme>rɪ'fju:z</phoneme> <lexeme> <lexeme role="wdn:noun"> <grapheme>refuse</grapheme>

<phoneme>'refju:s</phoneme> <lexeme></lexicon>

Example sentence:“I refuse to take the fridge as a refuse.”

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SSML should to be extended!

<?xml version="1.0" encoding="UTF-8"?><speak version="1.0" xml:lang="en-US" xmlns="http://www.w3.org/2001/10/synthesis">

<lexicon uri="http://www.example.com/example.pls">

I <token role="wdn:verb">refuse</token> to take

the fridge as a <token role="wdn:noun">refuse</token>.

</speak>

… and SRGS too!

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Other Issues for the Workshop

• Lexicon selection criteria in SSML

• Which phonetic alphabets?Current PLS 1.0 mandates the usage of IPA (International

Pronunciation Alphabet)Are there other options? We need standard alphabets!

• Other issues?