He was working fine for me this morning, loaded up my save and suddenly hes mute..

I know this discussion is old, but in case anyone wants to know a possible fix for the muted dialogue problem, I pasted this from my comment on the Nexus Mods page for this mod. I hope this helps.

*TO ANYONE HAVING PROBLEMS*

I had the same problems with this as everyone else no matter how many times I installed this mod. This mod seems broken upon first install, but this is not actually the case. The game itself just seems to struggle with initially loading the dialogue. There is a couple of steps you need to do to get the follower and all the included dialogue to load correctly.

*Note* From my own experience, this mod doesn't seem to be load-order sensitive. I had this mod placed further up, halfway and further down the load order and it makes no difference. Also don't worry about SKSE. I use it and it doesn't affect this.

Now, here is what fixed the issues for me. When you enter the Bards College after installing the mod, save the game and exit to the desktop. Open Skyrim again and load the save. Go to where Michael is and tell him to follow you. Go outside and fast travel to a location with a lot of enemies (I went to a Nordic ruin). Once you're there, save and exit to the desktop once more. Open the game again and load the save. Enter the location you just got to and engage in a fight. This should help trigger the additional dialogue not used when you're just trading things with him.

Doing all this seems to help the game to load the audio files correctly and let the dialogue play as intended. I know, this is a very strange "fix", but it does seem to work. Let me know if you have any issues and I'll see if I can give any more advice.