When DD7 was 2 or 3 communicating her thoughts and ideas was a challenge. Not because she couldn't explain things, but because she seemed to think that she had to use "grown up" words when explaining things to adults. Once we convinced her that she could just use "her words" and not ones she thought adults wanted to hear she was much more understandable. (by her words I mean words that she usually uses, not special ones)
We also had (and sometimes still have) difficulty stopping her from repeating herself when she has said something that she doesn't think explains her ideas "just right". She will then reword her ideas multiple times, or simply repeat herself until her words sound right to her, or she thinks that everyone completely understands her.
The most difficult part for her was not that we as parents would cut her off and try to get her to think before she repeated herself again, but that other people she was talking to would start ignoring her because they had lost her train of thought. (It turns out that the person was usually so amazed at what she was trying to explain that they had not heard her completely because they were too busy being shocked by her ability to talk and express herself.
)
DD is linguistically amazing, so her ability to verbally express herself is not usually a problem. Getting her to stop talking and explaining things is more often the issue.
