He goes from intrigued to mildly nervous to unhappy to downright alarmed over the course of those four words.

"That's terrible," he says. "That's completely—um. Here. I'll just." He does nothing obvious, but then he says: "'Shrennaki', try that," and it is definitely a word in definitely a language that bears a strong resemblance to Draconic but expresses no intrinsic opinions about shrens.