Voice AI: speech recognition, synthesis and assistants
Eight tasks for voice AI, a chain of models versus one voice model, tools for recognition and synthesis, seven rules of a good voice product and common mistakes.
In short
Voice AI consists of two technologies: speech recognition turns calls, voice messages and meetings into text, and speech synthesis reads text aloud in a natural voice. Together with a language model they make a voice assistant: it hears a question, understands it, finds the answer and replies aloud. The most practical uses today are transcription of calls with a summary for the CRM, voice messages in messengers turned into text, voiceover of content and a phone assistant for simple requests. The main difficulty of a live conversation is speed: a person notices a pause longer than a second, so every stage of the chain must be fast.
What voice AI is used for: 8 tasks
From the simplest — turning speech into text — to a live conversation.
| Task | Technologies | Effect |
|---|---|---|
| Transcription of calls | recognition + model | a summary and next steps in the CRM |
| Quality control of calls | recognition + model | all calls checked, not a sample |
| Voice messages into text | recognition | requests from messengers enter the usual queue |
| Notes of meetings | recognition + model | decisions and tasks without a note-taker |
| Voiceover of content | synthesis | videos and audio versions of articles without a studio |
| Voice menu on the phone | recognition + synthesis | “say what you need” instead of “press 3” |
| A phone assistant | the whole chain | simple requests at any hour |
| Accessibility | synthesis | the site can be listened to |
A chain or a voice model
A voice assistant is built in two ways: a chain of three models or one model that hears and speaks itself.
| Criterion | Chain of models | Voice model |
|---|---|---|
| How it works | speech → text → answer → speech | speech → speech |
| Speed | slower: three stages | faster, more natural |
| Control | every stage is visible and replaceable | less transparent |
| Knowledge base and tools | easy to connect | possible, with restrictions |
| Choice of voice | any synthesis, including your own voice | the voices of the provider |
| Log of the conversation | text at every step | needs a separate transcription |
| Best for | business requests with a knowledge base | live dialogue, practice, coaching |
Tools for recognition and synthesis
Cloud services and open models that run on your own server.
| Tool | What it does | Where |
|---|---|---|
| Whisper | recognition of many languages | open model, own server or cloud |
| Cloud recognition services | fast recognition, also in real time | Google, Deepgram, AssemblyAI |
| ElevenLabs | very natural synthesis, voice cloning | cloud |
| Voices of the model providers | synthesis and live voice dialogue | OpenAI, Google |
| Silero | synthesis of Russian and other languages | open model, own server |
| Kokoro | compact synthesis of English | open model, own server |
7 rules of a good voice product
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01
A budget for the pause
The whole chain fits into about a second; the model answers with a short first sentence.
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02
The right to interrupt
When a person starts speaking, the assistant stops at once.
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03
Short answers
What reads well on a screen sounds endless aloud — two or three sentences.
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04
Numbers and names aloud
Amounts, dates, codes and names are prepared for reading so the voice does not stumble.
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05
Noise and accents in the test set
Real calls from the street and the car, not studio recordings.
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06
A warning about recording
The person knows the conversation is recorded and processed.
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07
An honest robot
The assistant says it is an assistant and switches to a person on request.
Common mistakes with voice AI
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A text bot with a voice
Long answers with lists read aloud tire the listener in seconds.
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Pauses of several seconds
The person thinks the line dropped and starts talking over the answer.
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Testing in a quiet office
Real customers call from the street, and recognition falls apart.
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Wrong stress and numbers
A mispronounced brand name or amount sounds unprofessional.
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A cloned voice without consent
A voice is a part of a person; it is cloned only with written permission.
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No way to a person
A voice menu without an exit makes people hang up.
Questions about voice AI
How accurate is speech recognition?
On clear speech it is close to a person; noise, accents and special terms lower it — they are checked on your recordings.
Can a voice assistant answer phone calls?
Yes, through telephony: simple requests itself, the rest — to an operator with a summary.
Can I use my own voice?
Yes, synthesis services can clone a voice from recordings — with the consent of its owner.
Can recognition run on our own server?
Yes, open models like Whisper work locally — for recordings that must not leave the company.
Does it understand several languages?
Modern recognition and synthesis work with dozens of languages and can switch during a conversation.
What is the simplest place to start?
With transcription of calls or voice messages: the effect is immediate and nobody hears the robot.
Online form
Voice
for your product
I add voice where it is needed: transcription of calls and voice messages, voiceover and a voice channel for an assistant. Tell me about the task — I answer within one working day.