Why is there no Sound type? The groundwork is all there.

Super effective against Fairy, Steel, and Water
Not very effective against Bug, Ice, and Psychic

Resistant to Fairy, Ground, and Water
Weak to Bug, Psychic, and

Steel and Water are weak because those are susceptible to vibrations. Ground is resistant because Ground absorbs sound. Bug and Psychic are resistant because bugs make a lot of noise as is, and psychics keep their focus really well with the sound or something I dunno. Fairy and Ice are thrown in for balance reasons.

All Normal sound-based moves are changed to be Sound type.

Soundproof now works just like Levitate.

Pokemon lines changed to be sound type would include
>Exploud
>Audino
>Chatot becomes Sound/Flying
>Jigglypuff becomes Sound/Fairy
>Kricketune becomes Bug/Sound
>Ninjask becomes Bug/Sound
>Noivern becomes Sound/Dragon
>Chimeco becomes Sound/Psychic
>Meloetta becomes Sound/Psychic and Sound/Fighting