In Ren & Stimpy comics, Powdered Toast Man always referred to the product for which he was named as Powdered Toast® or Powdered Toast™. I always took that as a hint that he pronounced the marks somehow.
Why the downvotes for such a simple, factual statement that answered the question? If you do an internet search for the phrase "C in circle" you'll find it is a quite common way to describe this symbol. On the Wikipedia talk page, someone mentioned hearing this description in their school textbooks which were recorded in an audio version. Way back when I volunteered for Recording for the Blind (now Learning Ally) I recall that this was also the designated way to read this symbol.