I just listened to the first disc of a two-disc set of Cliff Richard, and I noticed two things about his cover of Ritchie Valens' "Donna."
At first, I just noticed that one of the lines could be written one of two ways. Either "For I love my girl; Donna, where can you be?" or "For I love my girl, Donna; where can you be?" There's a slight pause in the vocals after "girl," so the first rendering is more accurate, but the second is grammatically viable. There's no major difference in meaning between the two; one just has "Donna" as a vocative (asking her where she is), and the other has "Donna" as an appositive (specifying that the girl whom the singer/speaker loves is Donna).
But then I realized that this line (along with some others) illustrates something else. "For I love my girl; Donna, where can you be," "I had a girl; Donna was her name," and "Oh, well, Donna, now that you're gone" all have "Donna" in the middle of the line, which reflects how Donna is at the center of the singer/speaker's life and how her leaving is what he's most concerned about.
I briefly referenced Valens' original (I haven't gotten around to transcribing it yet), and while these two points also apply to his version, there are some slight lyrical differences between the two recordings.
