How to write annual review for subtle condescending employee behavior?

I have a star employee who has subtle condescending attitude causing minor communication boundary with other coworkers. I don't think he realizes it and I'm having trouble writing this part on his annual review. So far everything I wrote sounds mean and I don't want to shock him with abrupt review but these are the thinks that I want him to fix. How can I make it sounds constructive criticism not personality attack?