GNU Aspell is a free, open source and cross-platform spell checker and interactive spell checker program. It is designed to be a replacement for the Ispell program and it can be used as a standalone command line program, as a library, or as a plugin to a variety of applications. GNU Aspell allows users to quickly and easily check spelling in any text, including web pages, emails, documents, and more. It supports a wide range of languages, including English, Spanish, French, German, Russian, and more. It also provides an interactive mode that allows users to interactively correct spelling errors in real-time and a special mode for non-English languages. It is also able to detect and correct errors in words that are not in the dictionary, and it allows users to add custom dictionaries.
aspell is a CLI utility, Enchant is just a library.