Why is Penis spelt wrongly

So when it’s cut off it’s a “penum”?

verpa, perhaps…

A buffalo spelt is quite hairy and stinky.

Penis is not spelt wrongly, Anglophiles pronounce it wrongly. Most seem incapable of understanding Latin’s pronuntiation rules. There are valid historical reasons why penis is written the way it is and I am sure this fact is not going to change anytime soon.

Is this serious? Spelling does not dictate pronunciation. Speech is natural; writing is an artifice. It doesn’t matter what the origin of a word is.

what does the lovers of England have to do with the pronunctiaiton of the word?

You mean anglophones it seems: there is no reason for the average speaker of the English to know the rules of another language, certainlly not an old classical one.

The linguistic question no one has answered yet is, what process led the first vowel to change from a long e in Latin to a long i in English? The same great vowel shift which was by no means confined to Latin words? What caused it?

(If anyone adhered to the classical pronunciation while speaking English today, I suspect it would come off as a strong accent rather than a correct by-the-book pronunciation.)

Of course this is serious, in most languages spelling at least hints at pronunciation and usually helps to understand what the origin and the meaning of a word are. Sensible spelling should dictate pronunciation and does so in Latin, where the word penis came from. You anglophones (sorry I misswrote, wonder why auto-complete chose that option) pronounce it wrong.
BTW: Guess you never have wondered why you write pronunciation without but pronounce with an “o”? There is a reason for that. And the reason is that you pronounce both pronounce and pronunciation the wrong way, philologically speaking. Of course you are free to set arbitrary rules a posteriori, but do not expect me to find this a sensible course of action. Call me weird, but I find this hilariously funny.

I do mean anglophones indeed, sorry for my lack of attention with auto-complete. And of course there are lots of reasons to know things like the pronounciation of the words in another language that gave rise to the words in your language. That you choose to focus your attention on other subjects is your choice, you sure have your reasons too for that. But there are valid reasons to study philology, believe me. You can make a decent living of that and it is interesting.

[Moderating]
A reminder, everyone, to not make this personal.

Do they pronounce “meet” wrong? How about “house”? “Moon”?

If your point is merely that obviously foreign words should be pronounced as in the original language, then you have to decide if “penis” is a legitimate English word by now, or not yet. (First citation in the OED is from the 17th century. The vowel shift e -> i took place in the 15th century, according to Wikipedia.)