Voice Call System

I am looking for a reliable freelancer to develop a voice call system for mobile platforms. The voice call system should be able to support multiple languages, and the possibility of a text-to-speech feature. The system should provide crystal-clear calls with no interference. The system needs to be secure and safe to use, and the output should be of a high quality. If the freelancer can provide any additional features that go beyond the requested tasks, I am open to discuss these further. I look forward to reviewing your proposals!