Lesson 4 of 7
Turning speech into text
6 min read
An hour-long meeting, a voice memo, a podcast — and seconds later every word is written out, timestamped and searchable. How does audio become text you can read and search?
The reverse trick
The last lessons went from text to speech. This one runs the other way: speech to text. Feed the tool an audio recording — a meeting, an interview, a lecture — and it writes down what was said, word for word, with a timestamp on each line so you can jump straight to any moment.
Turning spoken audio into written text is transcription, or speech-to-text. Audio in, timestamped words out.
Audio in, text out
It doesn't just dump a wall of words. Good transcription tags each line with the time it was spoken, often labels who's speaking, and lets you search the whole recording for a word — so a two-hour call becomes something you can skim in a minute. Press Play below and watch the words appear in step with the audio, each stamped with its moment.
Transcription doesn't just write the words — it timestamps them (and often labels speakers), turning a long recording into something searchable.
Where it earns its keep
This quietly saves hours: automatic subtitles and captions, meeting notes you didn't have to type, searchable interviews for a journalist, a doctor's dictated notes. Tools like OpenAI's Whisper, Deepgram and AssemblyAI do the heavy lifting. It isn't perfect — names, jargon, crosstalk and strong accents still cause slips — so skim the result before you trust it.
For a clean transcript, feed it clean audio: one clear recording, minimal background noise, people not talking over each other. Garbage in, garbage out applies — a muddy recording makes a muddy transcript.
The gist
- —Transcription (speech-to-text) turns spoken audio into written words — the reverse of text-to-speech
- —It timestamps each line and often labels speakers, so a long recording becomes searchable and skimmable
- —Powers subtitles, meeting notes and searchable interviews (Whisper, Deepgram, AssemblyAI); check it for slips on names, jargon and accents
You record a one-hour interview and want to quickly find the moment someone mentioned 'budget', plus generate subtitles. What tool fits?
Continue in the app
Take the whole AI Voice & Speech course — tracked
Get your personalized path, progress and streaks in the app — this lesson and every next one, in order.