This is how Unicron talks to Twilight goes in The Crystalling.
[Twilight is sleeping when she hears Unicron's voice calling her name]
Unicron: Twilight. Twilight. Twilight.
Twilight Sparkle: Unicron?
[Unicron appears in Twilight's mind]
Twilight Sparkle: But how?
Unicron: You have a link with me and my followers because my life blood now flows through your veins.
Twilight Sparkle: Dark Energon.
Unicron: It binds you to my Anti-spark.
Twilight Sparkle: But Optimus used the Matrix to put you back into slumber.
Unicron: The Prime only rendered my material form dormant, but it was roused from slumber when I sensed the destruction of the Crystal Heart.
Twilight Sparkle: Shining Armor and Cadance's daughter.
Unicron: I now wish to take over the Crystal Empire.
Twilight Sparkle: So I will be able to remain me?
Unicron: Only to serve me. You will simply be an instrument of my will but you will not tell anyone you are.
[Unicron uses his power to turn Twilight into Midnight Sparkle and they fly to the Crystal Empire]
Twilight Sparkle: Magical transformation use. Impressive.
Unicron: One of my many talents.
Twilight Sparkle: So we are to make friendship last eternally?
[Unicron fires lightning at Twilight, making her scream in pain]
Unicron: You will make nothing. I travel to the Crystal Empire for one reason-to destroy Princess Celestia and Princess Luna personally.
Twilight Sparkle: But to destroy them is to destroy the Elements of Harmony.
Unicron: Thus will begin a new age-the age of real eternal chaos.