Hi Kushagra,
Unfortunately, RadRichTextBox does not support spellchecking for more than one language at the same time. The spellchecking functionality depends on the CurrentCulture in which the RadRichTextBox is running and it will automatically switch between all dictionaries in the DocumentSpellCkecker collection.
RadRichTextBox comes with a default English spellchecking dictionary which is ready to use if a reference to Telerik.Windows.Documents.Proofing.Dictionaries.En-US.dll is added. Any other dictionary could be added to the DocumentSpellCkecker collection of dictionaries (what we did in the demo project).
Please be aware, that because of the specificity of Arabic language should be done some additional changes. If you are going to use both English and Arabic dictionary, but one at a time, I would recommend you check the CurrentCulture and if it corresponds to “ar-DZ” culture to set the Arabic dictionary. The following code-snippet demonstrates how this could be achieved:
I hope this helps!
Do not hesitate to contact us back.
Regards,
Yancho
Telerik