This is an excellent question! (To save anyone the click, Katie's asking why we say 'wolf' and 'golf' differently.) Pronunciation in English is a storied, rambling topic.

*ahem* A thread. https://twitter.com/joan_of_orc/status/1328060544620892160

So English words don't necessarily have - and haven't historically had - the same pronunciation everywhere; accents, dialectical differences and other regional quirks vary the sounds of words considerably.

This has a bearing on spelling! Before English was standardised in the 9th century (largely by Alfred's efforts) and again from 1066 until about the mid 15th century (in part down to Henry VI), English was written entirely phonetically, which meant spelling varied by region.

Written English is a sort of fossil record; modern spellings tell you a lot about the date a word entered the language and was standardised (e.g., the spellings of 'grass' and 'path' suggest the modern Northern pronunciation was once standard).

(Dr Johnson threw an extra wrinkle in here in the 18th century, by his largely arbitrary selection of words for the dictionary; his researchers ranged all over, letting him pick and choose spellings from different accents. He also invented spellings, like the 's' in 'island.')

So how does this help us with 'wolf' and 'golf'? Well, let's see. If we can dig back and look at where the words came from, where they were used and how they entered the language, we may be able to deduce why they're pronounced the way they are now.

So my obvious first lines of enquiry are age ('wolf' is clearly the far older word) and geography (golf is famously a Scots invention).

First, age; 'wolf' is a pan-Germanic word, in constant use since ancient days (understandably, since wolves were a constant threat).

It's spelled 'wulf' (or variants like 'ulf' and 'ulv') everywhere across Northern Europe, and in England until the 12th century. This suggests the modern pronunciation has existed forever. The new spelling probably reflects an early-Middle English shift in how 'o' was said.

What we now think of as 'long' and 'short' vowels (as in 'met' and 'meet,' 'bat' and 'bate,' 'writ' and 'write,' etc.) is pretty modern. In Middle English they weren't actually pronounced differently, they were literally *short* and *long* but otherwise the same.

In the case of A, E and I, the modern 'short' pronunciation is more or less the same as it has always been and the 'long' pronunciation formed around the fifteenth and sixteenth centuries; but the opposite is true(ish) with O and U.

I remember my lecturer taught us to say "How now, thou brown cow?" in a ME accent, which sounded rather like "Hoo noo, thoo broon coo?"

By the same token, in the 12th century, the 'ol' in 'wolf' would sound something like 'ool' in 'wool' (indeed, 'wool' was spelled 'wolle').

So, basically, in the case of 'wolf,' it's always been pronounced that way, with only sight shifting, but the pronunciation was fixed at a time when spelling it with 'ol' made sense.

Now, 'golf'! For starters, that one came into the English language much later, in about the fifteenth century. Literacy was higher, so the spelling of the original foreign-language loan word (the Dutch 'colf,' for 'club') may have been imported with it.

The pronunciation would also have an impact, of course, and we can be pretty sure how the Dutch word was pronounced, since it's still in use today: https://en.wiktionary.org/wiki/kolf#Dutch 

It's a pretty distinct 'owl' rather than 'ool' sound.

(The game is still played too: it's sort of like billiards played with polo mallets on a plastic ice rink.
https://en.wikipedia.org/wiki/Kolven )

And it was imported to Scotland, which is important! Throughout history, when we talk about written English, we're talking about the English of London; we have source documents from all over the country, but the usages which become standardised are the fashionable London usages.

In the Scots accent, the word 'pull' (for example) is closer to the Southern 'pule.' While south of the border 'wolf' and 'wulf' might be more or less indistinguishable, it's definitely not the case in Scotland. So 'colf' really couldn't be spelled any other way.

And by the time the sport - and word - had spread across Britain, the spelling was fixed.

I hope this has been of use.