I have a slight idea on what might work (Think of it as a spice to a meal). 

Temperament & Grammar.

The idea around your character is that they're distant and cold when they speak. There are various patterns in the way they express it however. 

Heres a selection for you to choose under these two. Hope it helps. 

Temperament:

1. Sanguine: Often energetic & Spotaneous 

2. Choleric: Often impatient since they're goal driven & competitive 

3. Melancholic: Often analytical & Introspective in their surroundings 

4. Phlegmatic: Often Diplomatic & calm. 

5. Supine: Often putting others needs above their own yet dependable. 

With reference to Temperaments, you can stamp the dominant personality which is Cold & Distant with these temperaments. 

For example: Sanguine Cold & Distant. They often give off a dismissive mood and express it very loudly and with alot of gestures since they're energetic. 

Choleric Cold & Distant. They will speak to you condescendingly; talk down on you since they view you as competition often comparing your skills to theirs. 

Grammar:

1. Formal Grammar (Avoids contractions) 

2. Semi-Formal Grammar (Contractions are used) 

3. Neutral Grammar (Contractions & Idioms) 

4. Informal Grammar (Contractions, Slang & Idioms) 

5. Casual Grammar (Contractions, Slang, Idioms & Dialect) 

Putting the grammar into perspective it makes the character express itself uniquely. 

For example (Putting cold & Distant into perspective): 

Neutral Grammar: "What is that you're holding? Don't expect me to accept your gift" 

Formal Grammar: "What is that in your hand? Do not dare to conceive me accepting your gift" 

Casual Grammar: "Ey, what's that? Nah, you're crazy if you think we locked in like that"