Tone Changer for Writing — Shift Any Text from Casual to Formal on Mac

You wrote a quick message to your team: "Hey team, just wanted to quickly follow up on that thing we talked about. It's kinda urgent, you know? Let me know if you can get it done." It gets the point across — barely. But forward that same message to a client, a VP, or a partner, and the casual tone undercuts the urgency you're trying to convey. What you need is a tone changer for writing — not an audio voice pitch tool, but something that rewrites your words so they land with the right weight for the audience reading them.

WunderType is a macOS menu bar app that works as a tone changer AI for your writing across every app on your Mac. Select text, press a keyboard shortcut, and get back a version rewritten in the tone you need — casual to formal, rough draft to polished communication. No browser tabs, no copy-paste workflows, no separate writing tools.

A Tone Changer That Works Across Every Mac App

WunderType gives you AI-powered text actions through Custom Prompts. Each prompt carries its own instruction and keyboard shortcut, and it works system-wide — in Mail, Slack, Notion, Google Docs in your browser, Pages, or any app where you write. The tone transformation happens in place: select your text, press your shortcut, and the rewritten version replaces the original on the spot.

This is specifically about writing tone — the difference between sounding like you're texting a friend and sounding like you're addressing a boardroom. Not audio pitch shifting, not voice modulation. Pure text rewriting that changes how your words read and feel.

See the Difference: Casual Draft vs. Professional Message

Here's a real scenario. You dashed off an internal follow-up, and now you need it polished before it goes to stakeholders:

Before

Hey team,
Just wanted to quickly follow up on that thing we talked about. It's kinda urgent, you know? Let me know if you can get it done.

Select it, press ⇧⌘T, and WunderType delivers the professional version:

After

Subject: Follow Up Regarding [Topic]

Team,

This is a critical follow-up regarding the previously discussed matter. Please prioritize and confirm completion at your earliest convenience.

The transformation is comprehensive. Filler phrases like "just wanted to" and "you know?" disappear. The vague "that thing we talked about" becomes "the previously discussed matter" with a placeholder for specifics. The casual "kinda urgent" escalates to the precise "critical." Even the structure shifts — the rewritten version adds a subject line and uses deliberate paragraph breaks that signal professionalism before a single word is read.

That's the difference between a message that gets skimmed and one that gets acted on.

Why Writing Tone Matters More Than You Think

Tone carries meaning that words alone don't. The same request — "get this done" — reads as a friendly nudge in casual tone and a direct order in formal tone. Misjudge the tone and you either sound unprofessional when you need authority, or cold and distant when you need rapport.

Professionals switch between tones constantly throughout the day: casual in team Slack, formal in client emails, diplomatic in cross-department requests, concise in executive summaries. Maintaining the right tone for each context takes mental energy that adds up, especially when you're writing dozens of messages daily. A tone changer eliminates that cognitive overhead — you write naturally, then let the prompt handle the register shift.

Beyond Casual to Formal: Build a Full Tone Toolkit

A single tone direction rarely covers every situation. With WunderType's Custom Prompts, you create multiple tone changers, each with its own shortcut:

• Casual to Formal — transforms relaxed drafts into professional, polished communications
• Formal to Friendly — softens stiff corporate language into warm, approachable messages
• Blunt to Diplomatic — rewrites direct feedback with tact and constructive framing
• Verbose to Concise — strips filler and tightens rambling text into sharp, efficient prose

Each prompt gets its own keyboard shortcut. You build a tone toolkit that adapts to every audience and context across your Mac.

Set Up Your Tone Changer Prompt

1. Click the WunderType icon in your Mac's menu bar and open Custom Prompts
2. Create a new prompt named "Tone Changer" with an instruction like: Rewrite the selected text in a formal, professional tone. Remove filler words, slang, and casual phrasing. Use precise vocabulary and clear sentence structure. Add a subject line if the text is an email or message. Preserve the original meaning and intent. Output only the rewritten text.
3. Assign ⇧⌘T as the keyboard shortcut — it now works in every app on your Mac

Are AI Tone Rewriters Free to Use?

Many browser-based tone changer tools offer free tiers with strict word limits, ads, and the requirement to paste your text into a web form. WunderType takes a different approach: it connects to OpenAI (using your own API key) or runs entirely offline through Ollama with a local model. There's no per-word fee, no subscription to a writing platform, and no daily limits. Once set up, your tone changer works as many times as you need it — across every app, for any length of text.

With a local Ollama model, your messages never leave your Mac. Confidential client communications, internal strategy discussions, sensitive HR messages — they all stay on your device. No cloud processing, no third-party access to your writing.

Who Needs a Writing Tone Changer

Some roles demand constant tone switching more than others:

• Managers — who write casual team updates and formal executive reports in the same hour
• Freelancers — who match each client's communication style while maintaining professionalism
• Customer support leads — who turn internal shorthand into empathetic, polished customer responses
• Non-native English writers — who understand the content but need help nailing the right register
• Anyone emailing up the chain — where the wrong tone can change how your competence is perceived

Download WunderType from the Mac App Store and start changing the tone of your writing with a single keystroke.