Email, Messaging, & Video Calls Email How to Spellcheck as You Type in Mozilla Thunderbird by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on June 19, 2019 Dimitri Otis / Getty Images Email Yahoo! Mail Gmail Tweet Share Email It's an inescapable truth: If you type, you make mistakes. As fingers hurry over a keyboard, they sometimes hurry too fast and too far. Sometimes, it's not a typo; rather, it's a matter of not knowing how to spell a word you're unfamiliar with. Whatever the case, you usually can rely on Mozilla Thunderbird's spellchecker to catch—and correct—your typos. With inline spell checking, it even does so immediately, as you type. Check Your Spelling as You Type in Mozilla Thunderbird To have Mozilla Thunderbird check the spelling in the emails you write as you write them: Select Options from the Tools menu in Mozilla Thunderbird. (It's at the bottom of the Tools dropdown menu) Go to the Composition tab/category. Choose the Spelling tab. Make sure Enable Spell Check as You Type is checked. Click OK to close the Options window. While composing an email, you can turn the inline spellchecker on or off for just this message by selecting Options > Spell As You Type from the menu. Choose Your Language You also can specify the language Thunderbird is to use for spellchecking under Tools > Options > Composition > Spelling.