Dictation software has access to a lot. Not just what you write, but the drafts you delete, the messages you rephrase, the parts of a document you dictated before removing. If it's cloud-based, all of that transits someone else's infrastructure.
Whether that matters depends on your work. What shouldn't vary is understanding which one you've bought - and the vocabulary vendors use makes that harder than it should be.
Fully on-device. The model runs on your machine. Audio never touches a network. superwhisper, VoiceInk, MacWhisper, Handy, Parrot, Amical, Buzz, Vibe, Vocalinux, and Apple Dictation on Apple Silicon all work this way.
Cloud. Audio is uploaded, transcribed on a server, and text comes back. Wispr Flow, Aqua Voice, LumeVoice, Otter.ai, and every meeting assistant work this way.
Hybrid. Transcription happens locally, but a cloud language model cleans up the text - so your words leave the machine even though your voice doesn't. Or the reverse. Voibe is offline on Apple Silicon and zero-retention cloud on Windows and Intel Macs. Willow Voice is cloud by default with opt-in offline on Apple platforms only. OpenTypeless is only offline if you pair Apple Speech with a local Ollama model.
Hybrid is where most confusion lives, because the marketing describes the local half.
Four phrases that sound like on-device processing and aren't:
"On-device processing." Sometimes only wake-word detection or voice activity detection runs locally, with actual transcription in the cloud. Windows Voice Typing is straightforward about being cloud via Azure with a weak local fallback; not every vendor is that clear.
"Privacy Mode." Almost always a retention policy. Wispr Flow's Privacy Mode limits how long your data is kept, not whether it's transmitted.
"Zero data retention." Your audio is sent, processed, and not stored. It's a genuinely meaningful commitment - VoiceDash processes via OpenAI with ZDR, LumeVoice states ZDR and no training on user data, Voibe uses zero-retention cloud inference - but it isn't local processing, and it depends on the vendor honouring it.
"We don't train on your data." A commitment about use, not location or retention. Three separate questions: is it transmitted, is it stored, is it used for training. A vendor can answer no to the third and yes to the first two.
Turn off wifi. Unplug ethernet. Dictate a paragraph.
If text appears, the model is running locally. If nothing happens or you get an error, it's cloud. This takes fifteen seconds and settles the question more reliably than any privacy policy.
For a stronger check, watch outbound connections while dictating: Little Snitch or LuLu on macOS, ss -tp or a firewall log on Linux, Resource Monitor on Windows. Handy states it makes no network calls at all; Vocalinux has no cloud code path. Those claims are verifiable, and with open source you can read the code.
Note one wrinkle: several apps are local for transcription but still phone home for licence checks and updates. That's a connection, but not your audio. What you're looking for is a sustained upload correlated with you speaking.
Regulated work. If a policy or contract forbids sending audio to third parties, no retention promise substitutes for not transmitting. This includes a lot of legal work, defence, and anything covered by a client confidentiality agreement.
Confidential conversations. Journalists with sources, therapists, HR investigations, unreleased product work, M&A. The risk isn't vendor malice - it's breach, subpoena, or a retention policy that changes after you signed up.
Health information. Different rules; see below.
People who work offline. Planes, fieldwork, rural connections, secure facilities.
People who'd just rather not. A perfectly good reason, and local tools are now good enough that it costs you very little.
If you're dictating Slack messages to colleagues, and your employer already uses Google Workspace or Microsoft 365, your text is already on someone else's servers. A cloud dictation tool with a real security posture - Wispr Flow has SOC 2 Type II and ISO 27001, Aqua Voice offers zero data retention on Enterprise - doesn't meaningfully change your risk profile, and it gives you a better product.
Being clear-eyed about this matters. Choosing a worse tool for privacy you don't need is a real cost.
On-device processing doesn't make a tool HIPAA-compliant, and cloud processing doesn't disqualify one.
HIPAA is a legal framework covering transmission, storage, access control, audit, and breach notification. When protected health information goes to a vendor, that vendor must sign a Business Associate Agreement. Local processing simplifies this by removing the business associate - but the rest of the framework still applies.
In practice, clinicians use cloud tools with BAAs: Dragon Medical One, Freed, Suki, Abridge, Heidi Health. The on-premises exception is INVOX Medical, deployable on your own servers.
And a warning that bears repeating: Nabla's free tier reportedly comes without a BAA. "HIPAA-compliant vendor" and "your plan is covered by a BAA" are different statements. See HIPAA-compliant transcription.
Be honest about the trade.
Answers to 1 and 3 are usually in the privacy policy. Answers to 5 and 7 usually require asking.
Yes, categorically. If audio never leaves your machine there's no third party to breach, subpoena, or change its policy. Cloud tools can be well-secured, but that's a different guarantee.
Your audio is transmitted and processed but not stored. It's a real commitment and better than the alternative, but it isn't local processing and it depends on the vendor honouring it.
Wispr Flow is cloud-only, so audio is transmitted. Privacy Mode limits retention rather than transmission. The company holds SOC 2 Type II and ISO 27001, with a HIPAA-ready BAA on Enterprise.
On Apple Silicon Macs and recent iPhones it runs fully on-device once you've downloaded the language, so audio doesn't go to Apple. Intel Macs still use the server-based enhanced model.
Disconnect from the network and dictate. If text appears, it's local. For a stronger check, monitor outbound connections while you speak.
Local processing removes the business associate, which helps, but HIPAA also covers storage, access control, and audit. Most clinical workflows use a cloud tool with a signed BAA - see the best AI medical scribes.
Last verified: 10 August 2026.