I got 5 dice and opened EFF’s wordlist, and generated a random five-word passphrase (all letters small with spaces, no punctuation) for my PC.
The words were making up a meaningful scene in my mind, so I made a complete sentence out of the words by adding some more words (like of, from, a, etc.) and punctuation.
I am not able to decide which of the following thoughts is more dominant:
Benefit: I got some punctuation, a single capital letter and more words. So the "strength" of passphrase should increase.
Drawback: The virgin passphrase was quite random (nonsense), but the new sentence has got appreciable "real-world" meaning (sense) to it. It looks like a spam message generated by the method mentioned in this answer.