How does speech recognition work? How a caller’s voice becomes text
Sado AI team · · 5 min read
In short
Speech recognition (ASR or STT) is the technology that turns spoken words into text. On a call it listens in short chunks, works out when the person has finished, picks the most likely words from the sound and the context, and writes numbers and times as digits. Phone calls make it harder: the sound is narrow, there is noise, people mix Uzbek and Russian words and dictate numbers in pieces. Judge the quality not by an overall percentage but by what matters: phone number, name, date and address.
What speech recognition is
Speech recognition, called ASR (automatic speech recognition) or STT (speech-to-text), turns a voice into text. Voice search on your phone, video subtitles and voice-message transcripts all run on it.
In an AI voice operator it is the first link. The customer speaks, the system turns the speech into text, and the next part reads that text, works out what was asked and prepares an answer. If recognition gets it wrong, everything after it goes wrong too: if “Thursday” is heard as “Friday”, the customer is booked for the wrong day.
How a voice on a call becomes text
- The sound is cut into short chunks. The system doesn’t wait for the customer to finish; it works as they speak.
- It finds where a phrase starts and ends. It separates the voice from noise and watches the pauses: a short pause means the person is thinking, a longer one means they’ve finished. This step affects both how fast the answer comes and whether the operator cuts the customer off.
- Sounds become words. A neural network trained on many hours of recordings knows which sound is like which word and which word usually follows which. So after “two hundred…” it expects “thousand so‘m”.
- The text is tidied up: “ninety-one, five hundred twelve” → “91 512”, “half past ten” → “10:30”.
- The text goes to the next part, which works out what the customer wants and puts the answer together. The whole chain: what an AI voice operator is.
Why the phone makes it harder
- Narrow sound: a phone line carries only part of the voice, so sounds like “s” and “sh”, “f” and “p” start to sound alike.
- Noise: calls from the street, a car, a bazaar or on speakerphone.
- Mixed languages: “Zakaz bersam, dostavka bepulmi?” (“If I order, is delivery free?”) has Uzbek and Russian words in one sentence.
- Numbers: phone numbers are dictated in groups, prices are said as “one and a half million”.
- Names and places: Shahzoda, Abdurahmon, mahalla names and landmarks.
- Accents and fast speech: every region pronounces things a little differently.
Two things help against mistakes: a good model trained on phone speech, and repeating what matters. If the operator writes down a number and asks “91 512 45 67, is that right?”, a mistake is fixed on the spot.
How to test recognition quality
Specialists measure WER, the word error rate: wrong, missing and extra words ÷ all words spoken. For example, 14 errors in a 200-word conversation: 14 ÷ 200 = 7%. That is only an example. For a business, another question matters more: were the details you need written down correctly?
| What to check | How to test it | What a mistake costs |
|---|---|---|
| Phone number | Dictate it in groups: “ninety-one, five hundred twelve, forty-five, sixty-seven” | A manager can’t call the customer back |
| Date and time | Say “Thursday at four”, “the day after tomorrow, morning” | The customer is booked at the wrong time |
| Name | Give your first and last name, then check the record | A wrong name stays in the CRM |
| Address | Give a landmark: “Chilanzar, block 9, behind the bazaar” | The courier gets lost |
| Mixed speech | Drop a Russian word into an Uzbek sentence | The operator misses the question |
After each test, read the call transcript: you see exactly what the system heard. Make one call from a noisy place.
Speech recognition in Sado
Sado listens and speaks in Uzbek and Russian and understands words mixed in one sentence. If you dictate a number in groups, it doesn’t jump in after the first group; it waits for the whole number. The recording and full transcript of every call are kept in the portal, so you see what the operator heard and what it answered.
More: Uzbek-speaking AI operator and AI operator for incoming calls. Test it yourself: call 78 778 01 23 or try it live.
Questions
Are speech recognition and a voice operator the same thing?
No. Recognition only turns voice into text. A voice operator then understands the question, answers, books the customer and sends the result to the CRM. Short answers: FAQ.
Will it understand my accent or fast speech?
The surest way is to try it, speaking as you normally do. Call 78 778 01 23, then check what the operator understood.
Is there recognition with no mistakes?
No; on the phone even people sometimes mishear. That’s why repeating and confirming the number, date and address is a good habit, and the call recording stays in the portal.