Nylas Mail automatically checks your spelling as you type in the composer. Misspelled words will be underlined in red. You can right-click to choose from a list of suggested corrections or add the word to your dictionary.
Nylas Mail uses your operating system’s language as the spellcheck language. To change it, you'll need to change your system language in the Windows, Mac OS X, or Linux system settings. Older operating systems (Windows 7 and below, and Linux) may only have an English dictionary available.
For performance reasons, Nylas Mail will only mark only the first ten misspellings in each draft.