This is a feature among the Germanic languages (of which English is one). In German, these are called splittable verbs, and they can appear in two forms: "upst

This is a feature among the Germanic languages (of which English is one). In German, these are called splittable verbs, and they can appear in two forms: "upstep" and "step up," depending on the sentence structure. That makes "upstep" / "step up" seem more like a separate verb from "step," rather than just being the same verb with an adverb added on.