Transliterado is a free WordPress plugin that improves the transliteration of non-ASCII characters in slugs. It supports multiple languages, including Esperanto, Swedish, Finnish, Danish, Norwegian, German, Russian, and Bulgarian. By replacing the default ASCII filtering used by WordPress, it ensures that diacritics are preserved in slugs, enhancing SEO and user-friendliness for languages that require special characters.

The plugin allows users to select from different transliteration systems for each supported language, offering flexibility and customization. Additionally, Transliterado can retroactively update slugs for existing posts, pages, tags, and categories. The codebase incorporates elements from other plugins, making it a reliable choice for multilingual websites. The GPL license enables users to utilize the plugin at no cost, and contributions for additional language systems are encouraged.