Mom 123 this sound so much like DD4. She will substitute words. The faster she reads the quieter she gets until she is reading silently. I told her to read to adults like she was reading to a baby. This helps but she still tends to trail off. She also will make up words if she is not sure what a word is. She only dose this with words that do not affect the content. Sometimes she messes up very small words because she find them irrelevant to the content and is rushing. Lately she has been much more engrossed in the story line and comprehension and gets impatient if we ask her to read out loud. She will not take the time to sound things out unless she has to in order to understand the story, because she wants to get the story quicker.