Speak better English,
just by talking.

Yes. Plumb is free and open source. There is no subscription, no trial, no ads and no account.

Plumb finds your grammar mistakes as you type or speak and underlines them, then shows you why when you hover. It doesn't silently rewrite your text: you make the correction yourself, which is how the right grammar sticks.

Speak into Plumb. Click Speak and talk about your day, a meeting or anything you like. Plumb writes down exactly what you said, mistakes included, and marks the grammar slips you make out loud, so you can see and fix the ones you repeat.

Yes, if you're learning by writing and speaking. Plumb is a practice space: every note shows what to fix, and the Progress chart tracks your Correctness over weeks, so you can see your English improving. It's made for learners and non-native speakers who want to get better, not just get auto-corrected.

No. Plumb's writing model runs on your Mac, and your notes are plain files on your Mac. The only things Plumb downloads are its AI models, once: the writing model when you first open it, and the voice model the first time you speak.

No, and that's the point. Plumb marks what looks wrong and shows you why when you hover. You make the fix yourself, which is how you actually get better at English.

Grammar mistakes, sentences that don't read as correct English, spelling, capital letters and punctuation. It also shows the tone, emotion, confidence, clarity and formality of each sentence, and a Correctness score for the whole note.

Any Mac with Apple Silicon (M1 or newer) running macOS 14 or newer, with about 2.7 GB of free disk space.

Yes. After the one-time downloads (the writing model, about 800 MB, and the voice model, about 130 MB, the first time you speak), Plumb works fully offline.

Yes. Click Speak next to the note title and talk. Plumb writes down what you say and checks it just like typed text, so it catches the mistakes you make out loud too.

Plumb is a notes app built for learning. It runs entirely on your Mac, so your writing never goes to a server, it's free, and it shows you your mistakes instead of rewriting them for you. The Progress chart then shows how your English improves over time.

Open Terminal (Applications, then Utilities), paste the one-line command from this page and press Return. It checks your Mac, downloads Plumb from its GitHub releases, verifies the download against its published fingerprint, copies Plumb into Applications and opens it. It works on any Apple Silicon Mac with macOS 14 or newer, with nothing else to install first.

Plumb tells you when a new version is ready and updates itself with one click: it downloads the update, checks its fingerprint, swaps it in and reopens. You can also check any time in Settings, under Updates, or run the install command again.

Yes. It's a short script you can read before running it. It doesn't ask for your password or change any macOS security settings, it refuses a download that doesn't match its published fingerprint, and it only writes Plumb into your Applications folder. Plumb and the script are open source on GitHub.

Plumb catches most everyday mistakes, but no checker is perfect. Treat it as a learning aid, not an authority: if a mark doesn't look right to you, trust your judgement.