Hello! I have an experience with C, C++, as well as many other languages(both mainstream and not). I've used SDL 1.2 and SDL 2 in the past, so I know the framework. I've created an application that used SDL2 and had a sounds. If you are interested in my offer, please respond with more details - I'm interested in the sound files(format of the files) and how many levels do I have to add sounds to. It would also be good if you clarified(although I assume that you thought it is obvious) that you want to add background sound(theme); or maybe I assumed wrong, and you want themes and/or sounds for special effects. If you have limited time, that would also be an important information.
Your feedback could help us understand the problem and make sure you are satisfied with what you're paying for.
Best Regards,
Mateusz