Ideas on how to "un-muffle" audio?

[Mugsy]

I have an audio file of people talking that sounds like they were being smothered with a pillow (Charlie Brown’s teacher was more understandable.).

Is there a filter (or combination of filters) that would help clear up “muffled” audio?

TIA

[Trebor]

I need to unmuffle this unsavable audio

It was recorded on a phone with the mic being covered by a finger. Whatever improvement I can make to this audio is enough, at least to see what if I can use it in some way or I’ll need to do a voice over on the video.