☰ → Settings → Spell check underlines misspelled words while you type into a page — a search box, a form field, an email compose window, anywhere you'd normally type. It's off by default.

Turning it on

Check Enable spell check, then check one or more languages below it — more than one can be checked at once, so a bilingual page doesn't flag every word in the "wrong" language.

Supported languages

English (US), Spanish, French, German, Portuguese (Brazil), Portuguese (Portugal), and Russian.

Chinese, Japanese, and Arabic aren't offered here — Chromium's spellchecker is dictionary-based (Hunspell), and Chromium ships no such dictionary for those three; their word structure doesn't fit a word-list model the way the languages above do. All three are still fully supported by Translating a page, which runs through a language model instead of a fixed dictionary.

Why the dictionaries are bundled instead of downloaded

Left to its own default, Chromium downloads a missing dictionary from Google's servers the first time you turn a language on. Vodou bundles the dictionary files instead (the same ones Chrome itself ships) and points the spellchecker at them directly, so turning on a language never makes a network request — consistent with Vodou not phoning home for anything else, either.