I came over to this image post because I was trying to figure out if Vinyl Scratch ever officially spoke, and I guess this one IDW comic page is it.  
The one moment she actually says something.  
So I guess if she is capable of canonicaly speaking, I wonder what her voice sounds like, and why she doesn’t speak more often? Aside from the task of finding a voice actress to do the job.  
Right now I’m imagining her with the voice of Gaige from Borderlands 2,  
Vinyl never speaks, but when she does, its nerdy, goofy and she Doesn’t Stop Talking!  
At least that’s what I think, on the other hand I was fantasizing Vinyl in EG using sign language, but then I realized that sign language in for ponies would be awkward…

…if I saw it right, the reason why Mac is so incensed at “the navigator” is because it’s what came out from his attempts to look around on Sapphire Shores’s float… with all the background dancers imitating him.  
Basically an involuntary pantomime.

Big Mac needs to snap and go on a tirade at the end of that comic.

@misnamed
 
WELCOME TO HELL.

DJ Pon3 talked!
 
Cool cameo for Katie Cook, who are the others?

@misnamed
 
Jesus Christ,NO.

How long until we get a video of bronies doing the navigator in real life?

@Fortune  
Hmmmmm…
 
You make sense, friend…

@Starswirl  
It’s probably because there are specific steps that she can look up, memorize, and get mad at any pony who doesn’t follow them exactly.

@Housemaster  
Faust planned an episode about that….they decided not to do it…..Here’s hoping they eventually rethink it.

This can’t be right! Twilight Sparkle, dancing like a normal person?! Impossible!

@Prof.NightJack
 
@Housemaster  
Just need Big Mac to have his own show!

@Housemaster  
Need more Big Mac in the show PERIOD!

We need more of this expressive Big Mac in the show… in fact… we just need this to be an episode.