We recommend writing your request in your company’s working language or in the language that candidates should definitely speak. Feel free to mention any additional language skills required for your assignment. If necessary, you can attach a translation of your request. This ensures that your text isn’t too heavy. Another option is to write a short description of your request in several languages. You can then include more details in attachment.
A tip: do not ask for candidates’ mother tongue. After all, you want to make a selection based on their talents, knowledge and experience.