To be fair, when you gain most of your vocabulary by reading, you have to guess at pronunciation most of the time. I read voluminously as a kid but still mispronounce words which I feel very comfortable with!

I've caught myself doing this with more obscure (to me) words—ones that I only encountered in text and not in spoken conversation. Debian was one ("DEE-bee-an"). I was talking to a friend one day about it when I first started using Linux ("LIE-niks"!), and he was amused by my innocence :)

> And he did this with at least one other word ("requiem")!

Did he pronounce it "rek-WHY-em"? That would drive me insane.

One thing I've noticed is that if there is a word I only encounter in its written form, I only sight read it and don't pronounce it internally (I remember doing it with "Hermione" the first I read the Harry Potter series). It's almost like there's just a brief silence in my inner monologue. I can see how that might lead to odd pronunciations the first time I actually think about it.

One odd thing I've noticed about myself: when I read the word Linux silently, what I hear in my head is often "LIE-niks", but when I say it out loud it's always "LINN-iks".

And it's not like I'm on the verge of mispronouncing it and have to correct myself; it naturally comes out the right way. Just not when I read it silently.

I used to pronounce Debian and Linux exactly those ways,

He pronounced it re-KWEE-em.

He might have been reading those words like that for years... I know I mispronounce many words, I just don't know which ones :-)

He may have read the words hundreds of times, just not heard them (pronounced by someone who knows their common pronunciation).

I have absolutely no idea in which way "Heretic" wouldn't rhyme with "magnetic". I mean, mag-net-ik and he-ret-ik rhyme to my ears :)

I think that they meant the syllable that the accent is on. HARE-ə-tic vs. hare-ET-ic.

I would put the emphasis on the second syllable, like for magnetic. Is this incorrect? I'm a non native speaker.

A light emphasis on the first syllable would be correct. It shifts to the second syllable in a word like "heretical" (he-RET-i-cal). Webster's dictionary and Wiktionary seem to agree. Oxford would be authoritative for English itself, but I don't have access to that.

As a native US English speaker, it sounds far more natural to put the emphasis on the first syllable.