What is something about the people in the Glade that bothers Thomas?

From the text:

The language was odd, and none of the boys seemed to care whether he lived or died.

_____________________________________________________________________________________________________

“Better hope you never find out,” the kid answered, looking far too comfortable for the situation. He held out his hand. “My name’s Chuck. I was the Greenbean until you showed up.”
This is my guide for the night? Thomas thought. He couldn’t shake his extreme discomfort, and now annoyance crept in as well. Nothing made sense; his head hurt.