I know that when a sentence begins with "I wonder" followed by a question, it is typically ended with a period.
I wonder why that is.
However, when "I wonder" is moved to the end of the sentence, does the same rule apply?
Why is that, I wonder?
It seems harder to deny the writer a question mark in this case if one is felt.
Best Answer
Both are correct English.
The first sentence has an embedded question object complement of a mental perception verb, and, as described here, sentences like these are often intoned as questions, because they're intended as requests for information. When a writer wishes their sentence to sound like a question in the mind's ear of the reader, they use a question mark; otherwise, not. This is very ordinary.
The second sentence has undergone a Dislocation, wherein the embedded question is moved to the front of the sentence, presenting a question form and signalling a bald request for information. And therefore, it is almost always punctuated with a question mark in writing; this is also very ordinary.