Would you have been against Mirror!Spike talking?

[Slashy 101]

No magic, Twilight just taught him how to speak.

[Castle Bleck 19,166]

Maybe if he was a parrot instead.

[Scootalove 10,684]

Not really, you could make him a parrot if you want to.

[Moon Sugar 532]

She is all scientific. I'm sure she would have made some contraption for it or another. 

[cmarston1 5,951]

I wouldn't have really wanted to see that happen.

That would have taken way too long to be accomplished, or be fixed in such a short amount of time that Spike should have just talked from the get go.

[Slashy 101]

I wouldn't have really wanted to see that happen.

That would have taken way too long to be accomplished, or be fixed in such a short amount of time that Spike should have just talked from the get go.

She would have taught him to speak before the events of the story took place.

[cmarston1 5,951]

She would have taught him to speak before the events of the story took place.

 

At fist I thought you were talking about Spike from the first Equestria Girls moive, but now I realize you weren't.

But even than I don't think it would have a been a good idea.

The world of EQG outside of the mirror is supposed to be similar to our very own and such when the magical elements are added they are supposed to be surprising to the characters.

Having human world Twilight teach her Spike how to talk (instead of him initially appearing as a regular dog) wouldn't really fit with that.