Which tool is used to detect spelling mistakes in written text?

The correct choice identifies spell checkers as tools specifically designed to identify spelling mistakes in written text. Spell checkers function by comparing words in the text against a dictionary of correctly spelled words. When they encounter words that do not match any in their database, they flag these words as potential spelling errors. This process often includes suggesting alternative, correctly spelled words to help the writer correct the mistake.

While proofreaders focus on reviewing text for errors, including spelling, grammar, and punctuation, they do not rely on automated tools. Grammar checkers are aimed at identifying grammatical issues rather than solely spelling errors. Editing software encompasses various tools that can promote general text improvement, but its capabilities can vary widely and do not specifically emphasize spell-checking as a singular function like spell checkers do. Hence, spell checkers are the most direct tool for detecting spelling mistakes in written text.