Automatic Spelling Language is a Firefox extension designed to enhance the spell-checking experience by automatically adjusting the dictionary based on the input text's language. Utilizing the Compact Language Detection framework, this tool efficiently identifies the language and applies the appropriate spell check without sending any data to external services. The extension supports a wide range of languages, including but not limited to English, Spanish, Chinese, and Arabic, making it a versatile choice for multilingual users.

The extension works seamlessly across various platforms, including popular sites like GitHub, Gmail, and Wikipedia. Users can adjust settings if the spell-checking does not function as expected due to content preferences that may override the selected dictionary. For those who need to reset these preferences, the extension provides guidance on how to manage content settings effectively. This tool is especially beneficial for individuals who frequently work with multiple languages.