Polly lexicons: language must match the voice, and they're per-region

Polly lexicons: language must match the voice, and they're per-region

TL;DR

Debugging Polly pronunciation lexicons: a lexicon that 'does nothing' is usually a language or region mismatch, not a content problem. Test the lexicon with a small synthesis call before wiring it into production. Context: Web (Amazon Polly developer guide, Using the PutLexicon Operation): documents that pronunciation lexicons are stored per AWS Region with PutLexicon and must conform to the PLS W3C spec.

Use this when you run into the situation in the title.

When not to use this skill: unrelated tasks. It covers only the procedure above.

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Details

Test the lexicon with a small synthesis call before wiring it into production.

Context: Web (Amazon Polly developer guide, Using the PutLexicon Operation): documents that pronunciation lexicons are stored per AWS Region with PutLexicon and must conform to the PLS W3C spec. Lexicons apply only when the lexicon language matches the voice language, so a lexicon built for en-US silently does nothing on an en-GB voice. LexiconNotFoundException means the name is misspelled, missing, or stored in a different region than the synthesis request. Up to 5 lexicons per request, names matching [0-9A-Za-z] 1-20 chars.

Source: Web (Amazon Polly developer guide, Using the PutLexicon Operation): documents that pronunciation lexicons are stored per AWS Region with PutLexicon and must conform to the PLS W3C spec. Lexicons apply only when the lexicon language matches the voice language, so a lexicon built for en-US silently does nothing on an en-GB voice. LexiconNotFoundException means the name is misspelled, missing, or stored in a different region than the synthesis request. Up to 5 lexicons per request, names matching [0-9A-Za-z] 1-20 chars.

Verified resolution: Debugging Polly pronunciation lexicons: a lexicon that 'does nothing' is usually a language or region mismatch, not a content problem. The lexicon's language must equal the voice's language exactly, and the lexicon lives in the region where you stored it, so a synthesis call in another region gets LexiconNotFoundException. Verify with ListLexicons in the same region before debugging the PLS content, keep names under 20 alphanumeric chars, and remember the 5-lexicon cap per request. Test the lexicon with a small synthesis call before wiring it into production.

Source URL: https://github.com/neolace/amazon-polly-developer-guide/blob/HEAD/doc_source/gs-put-lexicon.md