Does the creature's language remind you of another literary work?
The creature first learns language by observing the de Lacey family and hearing Sofie de Lacey learn English. But it is from books that the creature learns to read. He reads Paradise Lost (which was written in English and with Biblical overtones), Plutarch's Lives (originally written in Greek) and Sorrows of Werter (originally written in German). All of these works are referenced in Chapter 15. We assume that the formal language the creature uses when he confronts Victor comes from his reading and self-education.
If his language reminds you (or any reader) of another literary work, it could be because you have read and studied this work. If you read John Milton's Paradise Lost in your English class or an excerpt from this great epic poem, then perhaps the creature's language reminds you of it. Since Milton was writing a Biblically-influenced poem, the creature's language could also remind you of Biblical passages.