Freddy, a lot of words in English are made up, built up out of, other words in older languages. di means 'two of', and is prefixed to lemma, which means the abstract of anything you take (like an assumption). About 2 seconds of google-fu turned this link up, which asserts many people were taught 'dilemna', and supposes that if 'hymn' or 'autumn' have silent 'n's, then dilemma could too...
Yeah, that's where I got the real education. Kinda makes me wonder about everything else we're taught.
Charlatan! I knew it! You alway say "I ain't that old" but any real rocker would have picked up on that reference. Here, I'll try again.... Doot do do do do doot doot.....