Blurt: Faithful, On-Device Voice Dictation for the Mac
Abstract. Typing is the slowest part of using a computer. Blurt removes it: hold a single key, speak, and clean, punctuated text appears exactly where your cursor is — in any application. Unlike cloud dictation services, every stage runs locally, so no audio or text ever leaves the machine. We describe a deliberately small system that values faithfulness over clever rewriting: it transcribes what was actually said, corrects only the spelling of known names and terms, and never paraphrases. The result is a five-megabyte application that responds within about a second and works offline indefinitely.
Overview
Blurt is a background utility rather than an application one sits inside. A small mark rests in the menu bar; there is no window to manage. Holding the push-to-talk key records while it is held, and releasing it inserts the recognized text at the active cursor. The intent is to make speaking into a field feel as immediate as typing into it.
Method
Audio is captured only while the key is held and is recognized on the device. Recognition is biased toward a user-supplied glossary of names and terms. A deterministic pass then repairs spacing and removes filler sounds, and the result is inserted through the system's standard text interface. No network is contacted at any point.†
Faithfulness
A large language model could rephrase speech into polished prose, but it cannot reliably distinguish a genuine self-correction (“make it 3 pm”) from a narrated one (“he said no, no, I'm here”), and it would substantially enlarge the program. Blurt therefore declines to rewrite. Recognized text is already well-punctuated; only safe, local edits are applied, and every word you spoke is kept.
Vocabulary
Proper nouns are the hardest case for any recognizer. Blurt allows the user to supply names, contacts, and industry term sets; these bias recognition toward the correct spelling and back a conservative correction step, so the words that matter are rendered correctly each time.
Results
| Property | Value |
|---|---|
| Audio or text sent off device | 0 bytes |
| Speech-to-text latency (warm) | ~1 s |
| Application size | ~5 MB |
| Applications supported | every text field |
| Accounts required | none |
| Offline after setup | 100% |
Availability
Blurt is available for macOS on Apple Silicon and is free to try. Setup takes about a minute and two permissions — the microphone, to hear you, and accessibility, to type into other applications. Both remain on the device.
† “On-device” means recognition and text processing run on your machine; no server is contacted.
© 2026 P99 Labs · Private by design · research@p99lab.com