The I before E rule is one of the most notoriously broken rules in the English language. If you’re not familiar with the rhyme, it goes like this: “I before E, except after C, or when sounded as A as in neighbor and weigh.”

Maybe you’ve chanted that rhyme to yourself when you’re not sure how to spell something. It seems pretty solid until you have to spell a word like weird, leisure, or caffeine, and suddenly the entire rhyme goes out the window. None of those words sound like A, nor do they have a C anywhere near vowel pairing. Once again, the rules of the English language have betrayed you.

How many exceptions?

The rule is broken so often that UberFacts tweeted in 2014 to say there are 923 words that didn’t apply — which is actually more words than follow it. The Washington Post breaks down a lot of these discrepancies and says there’s a one in three chance that a word will break this rule.

No, we won’t go through every exception, but we can at least show you patterns where the exceptions happen.

The most likely explanation for why this rule exists is that it targets a specific pronunciation. It doesn’t apply to words like “conscience” or “species” because of how you say the word. The I before E rule was meant for when “ie” makes a long E sound. The problem is, it has more exceptions than when it sounds like A.

Why do we break the rules?

The rule makes it seem like A sounds are the only exception. They’re not. The long E sound shows up in words like weird and leisure. So why do those words break the rule?

We all know English is complicated. In fact, some English words aren’t even English. We use plenty of loanwords from German, French, Spanish, Arabic, you name it. If the word isn’t English, there’s a good chance it doesn’t follow English language rules.

Pronunciation also matters. If the “ie” falls at the end of the word—like in “species”—then the rule ceases to matter. And it the vowels are pronounced separately, they appear as you say them, as in “conscience” and “science.”

English is the poster child for rules that are made to be broken. The I before E rule may be the most famous case of linguistic disobedience ever. If you have trouble with it, you’re not alone. There’s no way to revise the rule to accommodate all of the exceptions, which begs one last question: Should it even be a rule?