Hello, I would like to know if using the elvish language like the one used in the lord of the rings is authorized or do I have to create a fictional language? I know this language is also used in The witcher So tell me what you think and share some advice.
Are you claiming the Elvish language from the Lord of the Rings is the same one used in The Witcher? Soliciting or offering legal advice is generally not allowed in this forum, for a variety of reasons. My only comment is that I don't see why a language created by say Tolkien with original words and phrases would not carry the same copyright and intellectual property protections as anything else an author creates, and I'd consult an expert on these things before assuming any differently.
I don't believe the Witcher uses Tolkien's languages. Sapowski created his own speech based on a number of real European languages. As for Tolkien's language--legality aside, I'm fairly certain the Tolkien estate considers the language protected by copyright, so if you use it you're likely to draw their ire irrespective of whether they have a solid case or not.
I googled "Is Tolkien copyrighted?" and was directed to The Middle Earth website. Yes, everything in the Tolkien books is copyrighted. The Lord of the Rings and The Hobbit, and the places, items, characters and events depicted in those books and films represent our intellectual property. To use any of those names (trademarks) as a business name without permission is unlawful. https://www.middleearth.com/faq.html#:~:text=Yes.,name without permission is unlawful.