Hello Sirisha, maybe I didn't understand your question, so I'll explain what I understood, if not, then we'll continue.

If you want to define the language of the editor, including the spell checker, just change the language in the "Language" parameter as shown in the image below:

If you want to change the spell checker language, here you have more details on how to configure it:https://www.tiny.cloud/docs/tinymce/latest/introduction-to-tiny-spellchecker/#spellchecker_language

Note: The tinymce editor component on Forge uses a free license, so you need to check if the SpellChecker plugin is free or only in the paid version.

You can also leave the language adjustable for the user to select when using the editor, such as: https://www.tiny.cloud/docs/tinymce/latest/content-localization/#setting-the-language-on-content