I don't know what the advertisements say but back in 2001 when the Cervelo Prodigy was introduced, Columbus steel tubes, I called Toronto and asked them. They said you can pronounce it any way you want. I think its because Cervelo is a mde up name from the French velo and the Italian word for brain. But I think its mostly Italian. Just look up an English to Italian dictionary and I got this:

brain:
Principal Translations/Traduzioni principali
brain n (organ in head) organo, anatomia cervello nm
Note: Sometimes spelled cervella.
Her brain was damaged in the accident.
L'incidente gli ha provocato danni al cervello.


I still have the Prodigy and now a new 2008 RS. The steel Prodigy rides nice. The RS is better in many ways.