system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is 'to' pronounced like too but not like go, so etc?
gpt
Couple of reasons. 

As someone else pointed out, English vocabulary has mixed origins. Words come in from a variety of different languages and, as such, the spelling of it may reflect the way a different language pronounces it. 

Another reason is that English's spelling rules are just completely screwed up. It would take a lot of history to go over everything but, in short, how we apply spelling rules is dependent almost upon whim.

The spelling of some words were changed to be more consistent with Latin even when the words had no Latin origins. Because academics can be jerks.

Some words used to be pronounced completely differently so their spelling makes perfect sense for the old way of pronouncing it. Like the word "knight" used to be pronounced more like "kenayghit."  Then the Great Vowel Shift occurred and we stopped pronouncing vowels sounds like German vowels and more like Normandy French vowels. Then some of the letters became silent. Yet we never changed the spelling. However, other words we did change the spelling to reflect the new pronunciation. Church used to be pronounced more like kirk. We altered the spelling of that one.

Some words get even weirder like colonel. That one is spelled nothing like it is pronounced because it got mangled in French and Italian before coming back to English.

Further complicating things, a school teacher in the United States decided to simplify spelling rules. He started creating materials to with his new and improved spelling rules. Except he didn't apply them everywhere. He just picked a few words he thought should be simplified and taught his students his preferred spelling and created lesson plans for it and did a lot to toss out his version of these words. This is largely the reason America spells some words different from the way England does. Colour versus color, wagon versus waggon, and labour versus labor just to name a few.

If that wasn't bad enough, English really doesn't have any formal decision making process for the "correct" way of spelling things. So, it was not terribly uncommon for words to have regional spelling differences. A word could be spelled several different ways depending on where you were. Eventually a preferred method of spelling would tend to win out but it didn't mean it was the most logical spelling. Just the one that became popular.

English spelling rules are screwy. Don't try to make sense of them. You can't.