I pronounce SQL as 'sequel' because IBM's System R was the first SQL implementation and its query language implementation was called 'SEQUEL' for "Structured English Query Language".

No amount of mental gymnastics by following implementations, and whatever motivations they have (a desire to distance themselves from big blue or avoid trademark disputes) will erase that unassailable fact from history.

http://www.almaden.ibm.com/cs/people/chamberlin/sequel-1974....