VAPI•4mo ago

Can't add pronunciation rule

I'm trying to add a pronunciation rule.

I'm making a POST request with the following body to https://api.vapi.ai/provider/11labs/pronunciation-dictionary:

{
    "name": "Finance Dictionary",
    "rules": [
        {
            "stringToReplace": "INV-",
            "type": "alias",
            "alias": "I N V dash"
        }
    ]
}

{
    "name": "Finance Dictionary",
    "rules": [
        {
            "stringToReplace": "INV-",
            "type": "alias",
            "alias": "I N V dash"
        }
    ]
}

{
    "name": "Finance Dictionary",
    "rules": [
        {
            "stringToReplace": "INV-",
            "type": "alias",
            "alias": "I N V dash"
        }
    ]
}

{
    "name": "Finance Dictionary",
    "rules": [
        {
            "stringToReplace": "INV-",
            "type": "alias",
            "alias": "I N V dash"
        }
    ]
}

But I'm getting a 400 error with a response body of:

{
    "message": "Unsupported data type. Either file or rules must be provided.",
    "error": "Bad Request",
    "statusCode": 400
}

{
    "message": "Unsupported data type. Either file or rules must be provided.",
    "error": "Bad Request",
    "statusCode": 400
}

{
    "message": "Unsupported data type. Either file or rules must be provided.",
    "error": "Bad Request",
    "statusCode": 400
}

{
    "message": "Unsupported data type. Either file or rules must be provided.",
    "error": "Bad Request",
    "statusCode": 400
}

Why?

VapiAPP•9/18/25, 2:55 PM

Hi DeeGee,

To change the pronunciation of specific words using Vapi, you can create a pronunciation dictionary with custom rules. Here's a concise guide on how to implement this:

Create Pronunciation Rules: Define these using phonetic notation (IPA, CMU Arpabet) or alias rules.
Upload to Vapi: Use Vapi's API to create your dictionary.

   POST https://api.vapi.ai/provider/11labs/pronunciation-dictionary

   POST https://api.vapi.ai/provider/11labs/pronunciation-dictionary

Configure Your Assistant: Update your assistant’s voice configuration to include this dictionary.

   {
     "voice": {
       "model": "eleven_turbo_v2_5",
       "voiceId": "sarah",
       "provider": "11labs",
       "pronunciationDictionaryLocators": [
         {
           "pronunciationDictionaryId": "your-dictionary-id",
           "versionId": "your-version-id"
         }
       ]
     }
   }

   {
     "voice": {
       "model": "eleven_turbo_v2_5",
       "voiceId": "sarah",
       "provider": "11labs",
       "pronunciationDictionaryLocators": [
         {
           "pronunciationDictionaryId": "your-dictionary-id",
           "versionId": "your-version-id"
         }
       ]
     }
   }

Test Pronunciation: Verify the changes using a test call or the Vapi playground.

Detailed steps and examples can be found in the Pronunciation Dictionaries documentation.

Feel free to reach out if you need more assistance.

abstract-purpleOP•9/18/25, 4:44 PM

I've followed steps 1 and 2, as shown in my original post, but I'm getting a 400 response.

Why would that be?

VapiAPP•9/22/25, 2:03 PM

Hey, can you send me a screen recording video that walks through the issue you are facing? It would be easier for me to understand your issue and help you out with it.

abstract-purpleOP•9/23/25, 10:47 AM

No problem, I've solved it ... user error.

abstract-purpleOP•9/23/25, 10:51 AM

For step 3, am I right in thinking that can't be added through the Dashboard?

abstract-purpleOP•9/23/25, 11:03 AM

PS - Neither the Pronunciation Dictionaries Guide (https://docs.vapi.ai/assistants/pronunciation-dictionaries) nor the API doc (https://docs.vapi.ai/api-reference/provider-resources/provider-resource-controller-create-provider-resource) are correct in terms of the request and response bodies.

Pronunciation dictionaries | Vapi

Control how your AI assistant pronounces specific words and phrases

Create Provider Resource | Vapi

VapiAPP•9/24/25, 11:18 PM

For pronunciation dictionaries workaround, you can use replacementsreplacements : https://docs.vapi.ai/assistants/voice-formatting-plan#replacements

VapiAPP•9/24/25, 11:18 PM

And yes, these have to be added through the API

Can't add pronunciation rule

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