Multilingual
For most Americans, there is only one language necessary. We speak English. If we pick up a little Spanish or French in school, that makes us exotic. The Amish often speak two or three languages, German and Pennsylvania Dutch on top of English. In church, they speak German. The Dutch, they use outside of school, in general interactions.
Forbidden Vanity
The idea of wedding rings falls under the same scrutiny of wearing colors or other jewelry. These are vanity moves, forbidden in Amish culture, even for celebrations or weddings. The goal is to look as plain as possible.