Skip to main content
Rime’s models power the voice of your product, and pronunciation control makes sure brand names, product names, and domain-specific words sound right before they reach your users. There are three ways to control pronunciation:
  1. Check dictionary coverage to see whether a word is already pronounced correctly out of the box.
  2. Specify a custom pronunciation inline using the Rime phonetic alphabet.
  3. Request a dictionary addition from the Rime team.

​
Check dictionary coverage

Use the Coverage API to determine which words in your text are not yet in Rime’s pronunciation dictionary. Words that aren’t covered will still be spoken — the model predicts a pronunciation, which is often suitable when the spelling follows typical linguistic patterns — but it’s worth verifying uncommon words before they reach end users.

​
Specify a custom pronunciation inline

For Mist-family models, you can specify a custom pronunciation directly in your TTS request by passing a phonetic string in curly brackets and setting phonemizeBetweenBrackets: true. The strings use the Rime phonetic alphabet, which is inspired by IPA. See Custom pronunciation for the full reference.

​
Generate the phonetic string from audio

You can write phonetic strings by hand from the alphabet reference, or let Rime generate one for you: record the word (or synthesize it) and post the raw audio to the Phonemize API. 
curl -X POST https://optimize.rime.ai/phonemize \
     -H "Authorization: Bearer $RIME_API_KEY" \
     -H "Content-Type: audio/wav" \
     --data-binary @speech.wav
The response contains the phonetic transcription of the audio: 
{
  "audioId": "9b2d8ad2-0618-4e96-b255-98b2f7488061",
  "phonemeString": "h0El1o !",
  "authed": 1
}
Drop any trailing punctuation token and paste the string into your TTS request inside curly brackets — here, {h0El1o} — with phonemizeBetweenBrackets: true.
phonemizeBetweenBrackets works on Mist v1 and v2 only. It is not yet supported on Mist v3, Coda, or Arcana. For brand or product name pronunciations on those models, request a dictionary addition, or respell phonetically in plain English (accepting that this is approximate).

​
Request a dictionary addition

If a word is mispronounced and you’d like it fixed at the dictionary level, reach out to your account manager via Slack or email, or contact sales@rime.ai. Our linguists typically review and add new words within one week.

​
Tips

  • Check coverage regularly when working with new or domain-specific content.
  • Brand names, technical terms, and made-up words are the most common sources of mispronunciation — verify these first.
  • For flows where pronunciation control matters most, use Mist v1/v2 so you can correct pronunciations inline.