Answer:
The comment that shows Holden's sensitivity to language is that The Person decides to say to Holden a "crumb-bun"
Explanation:
In the book The Catcher in the Rye, by J.D.Salinger Holden's character get that name coming from a prostitute when he tells him to leave since he is not willing to have casual sex with her, the general traits of this character show him as a very critic person not only of others but himself too, besides he has very clear and stable ideas about human interaction. His way of speak and the use of vocabulary are quite notorious among others his age.