Ruh-roh! Why does Scooby-Doo speak so strangely? Being a dog is probably a contributing factor. But Kyle Hill of Discover magazine says that the famous mystery-solving dog also has a speech sound disorder. Which one? Speech sound disorders come in two types: phonetic and phonological. People with phonetic disorders have physical difficulty forming words. People with phonological disorders tend to add or substitute sounds when speaking.
Hill consulted Dr. Steven Long, Ph.D., a speech pathologist at Marquette University. Dr. Long thinks that Scooby has a phonological disoder. Specifically, Scooby has a Rhotic Replacement. Hill writes:
He told me in an email: “I would refer to [Scooby’s disorder] as a phonological as opposed to a phonetic disorder in that he shows a pattern of substituting and adding sounds in his speech rather than just distorting sounds.”
So in terms of a diagnosis, Scooby doesn’t distort words, he adds onto them. “Uh oh” becomes “ruh roh” and “apple” becomes “rapple.” The technical term for this, Dr. Long told me, is rhotacization. In linguistics and speech pathology, rhotacization means changing some consonant like /d/ or /l/ to an /r/. Though Scooby definitely adds an /r/ to words that don’t begin with consonants, this complete rhotacization still basically describes his speech.
Giving the honors to Dr. Long, after 45 long years of odd pronunciations, he offered me Scooby’s official diagnosis: “Rhotic Replacement”.
This is an affliction limited to cartoon dogs. If anything, humans have the opposite problem:
In fact, Dr. Long explained to me that what Scooby does is basically unknown among humans. When something is wrong with our speech, we tend to subtract from the complexity of the sounds we try to make, not add to them. For example, American children speaking General American English tend to derhotacize rather than rhotacize their speech like Scooby does, “…resulting in Elmer Fudd-like pronunciations such as his much quoted phrase ‘wascally wabbit’,” Dr. Long told me.
-via Ace of Spades HQ
https://en.wikipedia.org/wiki/Scooby-Doo
I always remember it as showing up in the mid-70s. Damn, I feel old.