My child talks fast and the words break down so I can't catch them. Is this different from stuttering? (Cluttering)

Similar to stuttering, and common in people with Down syndrome, is "cluttering." Its features include: fast speech; folding words together ("restaurant" -> "restrant"); frequent fillers like "um"; and jumbled word order. The usual approach is to draw the person's own attention to "speaking slowly," but for people with Down syndrome, it's effective for those around them to speak slowly and naturally bring down the person's speaking speed. This is because speaking speed is influenced by the speed of the conversation partner. The trick is to change how you yourself speak, rather than pointing it out or criticizing.