the below hints should help you adressing this issue:
1. Pronounce each word more clearly. Oftentimes people who speak too quickly tend to blur words together in a way that can be difficult to understand. Spend some time practicing how you enunciate words, especially when you string them together in a sentence. Don’t skip over any words, not even the small ones. Enunciate each syllable of every word. This will naturally slow down your pace of speaking.
2. Use your breathing as a natural helping mechanism. This is an exercise used by actors to improve their vocal presence. Before each sentence, take a full bellyful of air and then pour all the air into that one phrase. Relax. Then, take another full breath and speak the next phrase. Practice this technique first by whispering. Then repeat it in a conversational way, but again, pour all the air into each phrase and honor the silence between phrases.
3. Plan pauses into your sentences. Try to consciously pause within sentences, or to be more precise, between distinct messages you convey. This adds a lot of gravitas to your communication. Try and adhere to mental cues, like three beats in between two statements (you can discretely use your toes inside your shoes to keep track).
Hope this is helpful!