PLS Considerations on using PLS for Slovenian Pronunciation Lexicon Construction Jerneja Žganec Gros Alpineon d.o.o., Ljubljana, Slovenia Internationalizing W3C's Speech Synthesis Markup Language, Workshop II, Heraklion, Crete, May 2006

ALPINEon SI-PRON lexicon: –word list –lexicon format –phonetic transcription –morpho-syntactic descriptions Proposed extensions to PLS, SSML Conclusions

Language specifics Slovenian language: –Slavic language, 2 million speakers, over 70 dialects –complex inflectional paradigm (common to Slavic languages) including "dual" – like ancient Greek! –lexical stress position – undefined and moving, like Russian (unlike some other Slavic languages, e.g. Croatian never carries accent on the last syllable) –many homographs, usually POS info helps at disambiguation: example: On je. (He is/eats). auxiliary_verb/indicative

Pron lex Speech technology applications: –automatic speech recognition (ASR) –text-to-speech synthesis (TTS) –require consistent specification of pronunciation –Slovenian: lexical stress position not fixed -> pron lex crucial Pronunciation lexicons: –general: not supposed to be covered by PLS –application-specific word/phrase pronunciations application-specific proper nouns: personal&location names

SI-PRON wordlist: (a) 93,154 lemmas from SSKJ (b) over 1,000,000 word form derived from (a) – morphol. deriv. (c) additional word list: corpus-based search 20,000 most freq inflected word forms not covered by SSKJ lemmas (d) collocations, multi-word expressions SSKJ: Slovar slovenskega knjižnega jezika Word-list

Phonetic transcriptions SSKJ lemmas: –automatic derivation, based on dynamic/tonemic accent information –manual corrections for about lemmas (words of foreign origin) Word forms derived from SSKJ: –automatic: SSKJ lemma pronunciation look-up, inflectional paradigms Additional corpus-based word list: –automatic lexical stress assignment –AlpSynth grapheme-to-phoneme rule set

GTP rules 193 context-dependent grapheme-to-phoneme rules: Left context Grapheme string Right context Phonetic transcr. ExampleRule explanation occurs before each -r not followed by a vowel (Toporisic91, p.49) =mf[F]Simfonija in front of and is pronounced as a labiodental (Pravopis90, p. 145)

Transcription accuracy experiment reference: hand-crafted pron lex, 30K lexemes, no loanwords(!) automatic lexical stress assignment: 15% error rate lexical stress & o/e pronunciation known in advance: –transcription success rate 99.1% (0.6% handcrafting errors)  conclusion:  for semi-automatic derivation of phonetic transcriptions with a 0.3% error rate only lexical stress positions & e/o need to be manually validated

SI-PRON format LC-STAR lexicon specs – STTS (Shamas & v Heuvel, 2004) Pronunciation Lexicon Specification (PLS) –Version 1.0, W3C Last Call Working Draft 31 January PLS: –Ver 1.0 not designed for TTS internal lexicons –on the other hand, we want to have a stronger link between SSML and the lexicon –we are even thinking of introducing POS attribute into token-like elements! –leave these issues for PLS Ver 2.x or address them now?

Pronunciation variations multiple pronunciations: –several elements –preferred pronunciation: indicated by the prefer element usually the 1 st pronunciation from the SSKJ for some words, 2 prons are equally preferred, e.g.: - male Slovenian nouns, terminating with "ilec" like /borilec/, /darovalec/ -"iUts"/"ilts", "ilts"/"iUts", "ilts", or "iUts" -typically account for more fluent "iUts" or overarticulated "ilts" pronunciation

Extensions… proposed extension for PLS/SSML: –a new optional attribute for the element: pron-style attribute values: "fluent", "overarticulated" –pron-style also for other elements (linkage SSML-lex!):,,, another optional attribute for the above elements: emotion for expressive TTS ? -could this be covered by the new role attribute? -similar to, proposed yesterday

Extensions… PLS…. source/creator: –only the element –source of multiple pronunciations: useful info when merging multiple PLS dox some sources/creators may be more reliable than others… - additional optional attribute pron-source for the element

Extensions… part-of-speech tags: –Slovenian – complex inflectional paradigm –morphological, syntactic and semantic(?) descriptors welcome in future revisions of the PLS specification –SSML: POS tags could be defined as an optional attribute of the element  lemma, MSD attributes used in SI-PRON  MULTEXT-East MSDs (Erjavec, 2004) – Telri, Concede Multext-East LRs, EAGLES,TEI P4 compliant

MSDs

MSDs

MDSs TTS-internal lexicon (for high-inflected languages) –full-blown form (PLS or other) –compact lexicons: –exception lexicon –derivational scheme/paradigm for providing prefix/suffix morphological rules, indications of lexical stress position shifts (hardly an issue of PLS)

Conclusion possible extensions to PLS, SSML: –pron-style attribute –emotion attribute needed? –source/creator attribute welcome –morpho-syntactic, semantic descriptors

Alpineon ZRC-SAZU Fran Ramovš Institute of the Slovenian Language Project Partners L project –Research of Slovenian Language in Lexicography and Lexicology based on Digital Language Resources –Spoken representation of Slovenian words:

PLS THANK YOU FOR YOUR ATTENTION!