Recently, I pronounced the word enqueue as ahn-queue. The person I was talking to said he would have pronounced it with a more normal en sound (like in Ben or den).
I'm not sure why I thought that ahn- was the way to pronounce this—it seems to be wrong according to the dictionary.
Is there a pattern for which words allow or require en- to be pronounced as ahn-? Or is this just something you have to know word-by-word?