Where to apply for licenses for large and multilingual dictionaries? How to choose the right one?

Question

Mobile development

Good day, the task arose in the mobile application to translate the user's text right there in the chat, since the application is paid - please tell me if anyone has come across or knows where you can find such dictionaries that can be embedded in a mobile application with correspondence (android and iphone), how much such a license costs, are there any pitfalls when communicating with license holders, and how to choose the right one based on what will be implemented directly.
Thanks in advance.
Sincerely, Victor.