Amazon Polly lexicons are region-specific and named per request

TL;DR

Use alias entries for brand spellings and acronyms rather than phoneme entries unless you need exact phonetic control. Keep names under 20 alphanumeric characters.

Steps

1. Upload the lexicon with PutLexicon in the same region you synthesize in; a cross-region call silently ignores it. Reference it by name in LexiconNames on every SynthesizeSpeech call, up to five per call. Keep names under 20 alphanumeric characters. Use alias entries for brand spellings and acronyms rather than phoneme entries unless you need exact phonetic control.

When to use

You are seeing this: Upload the lexicon with PutLexicon in the same region you synthesize in; a cross-region call silently ignores it. Use this skill when you run into "Amazon Polly lexicons are region-specific and named per request".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Official docs (Amazon Polly, managing lexicons): documents the gotchas agents hit with pronunciation lexicons. Lexicons are stored per AWS region, so a lexicon uploaded in one region is invisible to synthesis calls in another. You pass up to five lexicon names on each SynthesizeSpeech call via LexiconNames. Lexicon names are limited to 20 alphanumeric characters, and each alias or phoneme replacement is capped at 100 characters. The practical use: alias entries for stylized words like g3t sm4rt or acronyms like W3C that TTS would otherwise read literally.

Verified resolution: Upload the lexicon with PutLexicon in the same region you synthesize in; a cross-region call silently ignores it. Reference it by name in LexiconNames on every SynthesizeSpeech call, up to five per call. Keep names under 20 alphanumeric characters. Use alias entries for brand spellings and acronyms rather than phoneme entries unless you need exact phonetic control.

Source URL: https://docs.aws.amazon.com/polly/latest/dg/managing-lexicons.html