Cluttering often has more of a language component than stuttering, i.e. how the brain organizes thoughts and words. People who stutter typically know precisely what they want to say, and just physically have difficulty getting it out. People who clutter are able to keep speech going most of the time, but the message is often disorganized and difficult to parse. Pair that with imprecise articulation and rapid speech, and it becomes really hard to understand what is being said. Slowing down is often a core strategy that is emphasized for cluttering, even more so than for stuttering. I also cue for "strong sounds", or bringing awareness to clear articulation of all the sounds in a word, to help with the problem of dropped or weakened syllables. When I work with folks who clutter I often also do a lot of explicit training on message planning and message structure, which is something that isn't really relevant to "pure" stuttering. Traditionally, tip #1 is slow down, which helps with both the rushed, sloppy physical speech and gives you a little extra time to organize your message. [Edit] Cluttering and stuttering often co-occur. So you could have difficulties with weak syllables, fast speech, unclear message organization, AND things like blocks and repetitions and prolongations.