How prefixes reshape verb meaning & aspect
Most Russian verb roots describe a general domain of action, говори́ть (speech-related), ходи́ть/идти́ (foot-motion), писа́ть (writing). Prefixes attach to that root and narrow it down: direction, completeness, duration, repetition, or relationship between participants.
The same prefix often means different things depending on which verb it attaches to, раз- means 'mutual conversation' on говори́ть but 'smashing apart' on бить. Don't expect one-to-one translations; instead, build intuition for the general flavor each prefix adds, then let context fill in the specific meaning.
Many prefixes also serve a second job: turning an imperfective verb into a perfective one (see Aspect-Shifting Prefixes below). When a prefix appears to do 'nothing' semantically, it's often just there to mark the action as a completed, one-time event.
These prefixes attach mainly to motion verbs and indicate direction. They're the most visually intuitive, each one maps to a spatial concept.
These prefixes are primarily about turning an imperfective verb into a perfective one, adding the sense of a completed, one-time action. The prefix itself often carries little independent meaning beyond "this happens once, to completion."
These prefixes describe the *outcome* or *intensity* of an action, completion, excess, mutual exchange, or thoroughness.