VAPI•3mo ago

SSML its not working properly, Please Help!

The AI assistant is not pronouncing some of the words right, and I am trying to solve that with SSML.

I am trying with SSML because I have tried to solve these issues with Pronunciation dictionaries but I couldn't solve them, I am new to VAPI!

I am using a query tool to get more information from file which is called Knowledge Base.

When I am adding the SSML for those keywords inside the System Prompt, for example:

<phoneme alphabet="ipa" ph="taɪv">Tive</phoneme>
<phoneme alphabet="ipa" ph="ˈtaɪv soʊloʊ faɪv dʒi">Tive Solo 5G</phoneme>

for the Tive it works but for the Solo 5G it doesn't, its saying 5 grams.

Should I add SSML to the file which acts as a knowledge base or not?

How should I solve this?

Thank you!

Vapi Support BotAPP•9/23/25, 5:42 PM

Suggestion:
For reliable pronunciation of "Tive Solo 5G", use a pronunciation dictionary with a phoneme rule instead of SSML in your system prompt or knowledge base file. Here’s a sample rule to add via the API or dashboard:

{
  "stringToReplace": "Tive Solo 5G",
  "type": "phoneme",
  "phoneme": "/ˈtaɪv soʊloʊ faɪv dʒi/",
  "alphabet": "ipa"
}

{
  "stringToReplace": "Tive Solo 5G",
  "type": "phoneme",
  "phoneme": "/ˈtaɪv soʊloʊ faɪv dʒi/",
  "alphabet": "ipa"
}

This ensures your assistant always pronounces the phrase correctly, regardless of where it appears in responses or knowledge base content.
See full guide

Source:

Pronunciation dictionaries

⤵️ Mention @Vapi Support Bot for follow-ups 🐥

dead-brownOP•9/23/25, 5:44 PM

Do the pronunciation dictionary works only with elevenLabs or can I do it direclty using the VAPI API?

dead-brownOP•9/23/25, 8:57 PM

The name Solo 5G, is the name of a product.
The problem for this is this part: (5G), where the number is being pronounced correctly but the letter its not.

For the G the assistant is saying grams!

dead-brownOP•9/23/25, 9:17 PM

Nice!

Where should I put that line of SSML?, in System prompt or in Knowledge Base file @Lordvickthor

VapiAPP•9/25/25, 5:28 PM

You should put the SSML line in the Knowledge Base file. The System prompt is typically used for configuration, while the Knowledge Base is for the content itself. Let me know if you need any more help with this.

dead-brownOP•9/26/25, 1:21 PM

Hi, I have created a small knowledge base file, just with these specific key words like: Tive, Solo 5G etc, but the pronounciation is not working properly!

dead-brownOP•9/26/25, 1:21 PM

I don't have any other idea how to make this work!

dead-brownOP•9/26/25, 1:25 PM

Even the first message, where assistant speaks first, its saying it wrong, "Tive".
Where is saying like Tiv , where the word rymes with the word "Dive"

SSML its not working properly, Please Help!

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