Spellless

Stop spelling. Start writing.

Spellless takes your approximate spelling and offers you the word you meant. Drop the vowels. Get the letters out of order. Run two words together. Then glance, pick, and keep going.

recieve       →  receive           an ordinary typo
mthmtcs       →  mathematics       the vowels are gone
brcrtc        →  bureaucratic      a word you could not have spelled
satfcatn      →  stratification    a letter or two a syllable
exactlyright  →  exactly right     run together
sth           →  something         your own shorthand
grthndck      →  Grothendieck      a name, after you have typed it once
kubectl       →  kubectl           left alone

→ means "on the list", not always "at the top of it". Every change is one you picked: the list appears, you choose, and Enter always commits exactly what you typed.

It becomes one of the input methods in your keyboard menu, on Windows, macOS and Linux, so it is there in every program you type in. The word you meant is first 89.8% of the time, and in the top five 99.3% — measured on ten fresh draws the tuning never saw, ± 0.6.

Around that, the small things stop needing attention. Spaces appear between words and never in front of a comma, sentences start with a capital, eg becomes e.g. and i becomes I. A colleague's name is remembered after you type it once, and a correction you make twice leads that input from then on. When it does get something wrong, one key makes it forget. The space bar takes whatever is first, and a word the dictionary has never seen takes two presses of it.

Why this is an input method and not a spell checker: MANIFESTO.md.

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Install

For the best experience, use the Spellless builds of Rime below. They add a few small integration features that stock Rime cannot provide.

Already use Rime and want to keep it? Spellless works there too — docs/INSTALL.md has all six routes in, and what each one trades.

	recommended
Windows	One file. Download spellless-<version>-installer.exe and run it — Spellless is already inside.
macOS	Install Spellless-Squirrel-<version>.pkg, log out and back in, and add Squirrel - Simplified in System Settings → Keyboard → Text Input (it is filed under Chinese, not English). Then unzip spellless-<version>.zip and run python3 scripts/install.py inside it.
Linux	Build spellless-fcitx5, then unzip spellless-<version>.zip and run python3 scripts/install.py inside it.

The downloads are on Releases. Afterwards, click Deploy in the Rime icon's menu, then press F4 and choose Spellless from the list. Type zzver anywhere to confirm it is running.

Python 3.8+ runs the installer, and on Windows you do not need even that.

If something does not work, docs/TROUBLESHOOTING.md.

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What it can do

• Fuzzy candidates. Typos, transpositions, doubled and missing letters, and misspellings much worse than autocorrect would attempt.
• Incomplete spellings. Consonant skeletons (mthmtcs), syllabic shorthand (satfcatn), and completions from a prefix.
• Words it has never seen. Coinages get built from affixes (resmplng → resampling), and words run together come apart (exactlyright).
• It learns. A word you commit once is a candidate for ever, a correction you make twice leads the list from then on, and one key makes it forget.
• Your own vocabulary. A plain-text word list, a shortcut file, and eight importable packs — algebra, topology, software, philosophy and more.
• Capitals you never think about. Sentence capitals, acronyms, and spellings that resist both (iPhone, LaTeX, arXiv).
• Literal typing, always. What you typed is on the first page; a tapped Shift leaves Spellless entirely; a caret inside a word means plain typing; $ hands the keyboard to maths.
• Short input and notation commit as themselves: x, cm, PDE, 4D.

docs/USING.md is the whole of it — every feature, every key, and how the personal vocabulary files work.

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Documentation

MANIFESTO.md	what problem this is, and why it is shaped this way
docs/USING.md	every feature, the keys, and your own vocabulary
docs/INSTALL.md	the six routes in, and everything you can change
docs/TROUBLESHOOTING.md	symptoms, and what each one usually is
DESIGN.md	the architecture, and why each decision went that way
docs/RANKING.md	why that candidate is first: every mechanism that orders the list
docs/ALGORITHM.md	the matcher in full, with the evaluation
docs/NOISY-CHANNEL.md	the same algorithm as a decision problem over noisy channels
EVALUATION.md	accuracy and latency, and how to reproduce them
docs/PIPELINE.md	every step from keystroke to candidate, in pseudocode
docs/DEPLOYING.md	how a build reaches the input method, and the ways it silently does not
docs/SNIPPETS.md	writing maths with an editor's snippets
docs/RELEASING.md	cutting the archive and the bundled installer
data/README.md	the corpus, its provenance and its weaknesses

Development

make            # dictionary + indexes + test set
make test       # 2,327 assertions
make bench      # accuracy and latency over tests/cases/
make install

The tests and benchmark need a lua binary (5.4). generated/spellless.build.json records the sources, their SHA-256 sums and the parameters used.

Our builds of Rime live in their own repositories: spellless-weasel (Windows), spellless-squirrel (macOS) and spellless-fcitx5 (Linux, and the roughest of the three).

There is also a typing bench — docs/typing-bench.html, open it in a browser, nothing to build — which scores six public-domain passages by minimum edit distance.

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Limitations

The ones you will meet in practice. DESIGN.md §9 has the full list and the reason behind each.

1. One composition is one word. mthmtcs s hrd is three commits, and a digit ends a word — type Lean, commit it, then 4.
2. The fuzzy readings do not compose. exactlyright gives exactly right, but a run-together that is also misspelled does not, and shorthand with a slip inside it usually cannot be reached.
3. Very short input is genuinely ambiguous: frm offers from, form, firm, farm, forum, frame in frequency order.
4. On the standard Rime, spacing and capitals are guesswork. A click that moves the cursor is invisible to Spellless, so you will occasionally get a stray space or capital. Backspace re-syncs it, either can be turned off, and our own build does not have to guess.

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Licence and data

Code: MIT. Dictionary: derived from the SymSpell frequency dictionary (MIT); see data/README.md for provenance, preprocessing and counts.