Emoji, which have grown from an original set of 176 characters to a collection of over 3,000 unique icons, present both opportunities and challenges to the academics who study them. Most agree that the icons are not quite a language—the emoji vocabulary is made up almost entirely of nouns, and there’s no real grammar or syntax to govern their use—but their influence on internet communication is massive. By 2015, half of all comments on Instagram included an emoji.