Speech-to-text and text-to-speech explained simply

What is it?

Speech-to-text (also called speech recognition or transcription) turns spoken audio into written words. Text-to-speech does the reverse: it reads written text aloud in a synthetic voice.

Modern systems are trained on large amounts of recorded speech, so they handle many accents and languages far better than older tools. Voice assistants combine both: they listen, understand the request with a language model, and answer out loud. Some services can also copy a person's voice from a sample, which is powerful but needs consent and care.

Which models use it?

Whisper from OpenAI is a widely used speech recognition model.
Google, Microsoft and Amazon offer speech-to-text and text-to-speech in their cloud services.
ElevenLabs provides text-to-speech and voice tools.
Phone assistants and dictation features, such as those on Android and iPhone, rely on speech AI.
Voice modes in assistants like ChatGPT and Gemini let you talk with the model.

How to use it

For transcription, record in a quiet place with the microphone close to the speaker.
Tell the tool the language, and add unusual names or terms if it lets you add a vocabulary.
Read through the transcript and fix names, numbers and technical words.
For text-to-speech, write short sentences and spell out how unusual words should be said.
Pick a voice, speed and tone that suit the audience, then listen to the whole result before publishing.

Benefits

Fast notes and subtitles from meetings, lectures and videos.
Makes content accessible for people who are deaf, hard of hearing or have low vision.
Hands-free use of devices while driving or cooking.
Lets one script be voiced in several languages.

Limits and risks

Accuracy drops with noise, strong accents, crosstalk or specialist vocabulary.
Transcripts can contain wrong words that change the meaning; check before relying on them.
Voice cloning can be used for scams; only clone a voice with the person's clear permission.
Recordings may contain private information; follow local laws on recording and consent.

Prompt template

Copy it, replace the parts in [brackets] and paste it into any AI chat.

Here is a transcript of [a meeting / a lecture / an interview] about [topic]:

[paste transcript]

1. Fix obvious transcription errors, but mark any word you are unsure about with [?].
2. Split it into paragraphs with speaker labels if they are clear.
3. Write a 5-point summary and a list of action items with owners.
Keep the original meaning; do not add anything that was not said.

Speech-to-text and text-to-speech