Considering that he pronounces his last name to what appears to be "woof" I would think that yes, he may possibly have difficulty pronouncing this particular sound. You have probably noticed many people have difficulty pronouncing this word!
I am a student in speech-language pathology, and have worked in this field for over 7 years. This does not qualify me as an expert, so your question would be best answered by a clinically certified speech-language pathologist. Either way, he is an entertaining person and I enjoy his American Pickers show!
A person who mispronounces words may be referred to as having a speech impediment or a pronunciation issue. Sometimes it may also be described as a speech error or a misarticulation.
In the Bible, Moses is described as having a speech impediment.
If Jim has a lisp, then he has a speech impediment.
Davy has a speech impediment The country's debt has been an impediment to development. A speech pathologist will work with that little girl who has a speech impediment. After the doctor received the million dollar grant from the university his research continued without further financial impediment.
If a car stops in the middle of the road, it is an impediment to the drivers behind it. I speak with a lisp, therefore I have a speech impediment
War is one of the greatest impediments to human progress. Lack of confidence is an impediment to success. He suffers from a speech impediment:
Julia Child did not have a speech impediment. However, she had a distinctive, lively way of speaking that was a result of her enthusiasm and passion for cooking.
Consider it a speech impediment.
Lisp
He lisped because of a speech impediment. The impediment prevented them from making it through the ditch. The lack of funds was the impediment that ended the research.
There are various types but all involve the inability to form or pronounce words. A common impediment is stuttering.
There is no public information or evidence to suggest that Blake Lively has a speech impediment. Speech impediments are specific communication disorders that affect the production of sounds, and unless confirmed by Lively herself or a reliable source, it would be inappropriate to make assumptions about her speech abilities. It is important to respect individuals' privacy and not speculate on personal matters without concrete evidence.