Regardless of your regional accent, the word is made up of the "teli" from television and the "sini" from cinema. My own brand of mild Derbyshire is not exactly The Queen's English, but I do say "sini-mer" (the "er" is a shwa vowel sound like - excuse the example - the ending of enema, or the beginning of ago).
Anyway - potentially another controversial issue - how many bytes are there in a gigabyte?