Furthermore, there's the QUEL language, and SQL is probably going off that, especially with the original name of SEQUEL. Here's an interesting post on it: http://patorjk.com/blog/2012/01/26/pronouncing-sql-s-q-l-or-...

FWIW, I use sequel as that's how I learned it. But I also dislike unnecessary syllables so that's my justification.