Spell Checking in Gmail

It’s easy to check your spelling while composing Gmail messages. Here’s how:

• Click ‘Check spelling’ along the top of the message you’re composing.
• Click the misspelled word (highlighted in yellow) to see Gmail’s suggestions for similar words.
• Select a suggested word from the list to replace the misspelled word.
• Click ‘Done’ along the top of the message to continue composing, or click ‘Send’ to send your message.

Gmail’s spellchecker operates in the same language you’ve selected for your interface. If you compose a message in a language other than your interface language, you can check the spelling of that message, too — just click the arrow next to ‘Check spelling’ to select the appropriate language.

This feature is not available in Gmail’s basic HTML view. [source]