Nathaniel is a curate, or village preacher. As a man of the cloth, he is educated enough to speak Latin with Holofernes. But he's definitely subservient in that relationship, lapping up every long-winded word the schoolteacher utters. His star turn is in reading Berowne's letter to Rosaline, mistakenly received by Jaquenetta.
Because Nathaniel is celibate and prudish, there is extra comic oomph in his uncomfortable recitation of the sweet talk.