That refers primarily to people or things; which refers primarily to things, and who refers primarily to people. Some authorities insist who/whom be used when making reference to people, but others, such as the Merriam-Webster dictionary, write that such prescriptions are "without foundation" and use of that in such positions is common and "entirely standard".[2] Hence, one sees both "he is the man who invented the telephone" and "he is the man that invented the telephone."
It's true. In English we string words together instead of putting them into one word, so there's not really much difference beyond the odd bit of morphology.
Thanks for sharing this, it's got me going down a rabbit hole now! There's just so much stuff surrounding Judaism and early Christianity that you just don't hear about or engage with meaningfully or critically as a Christian, so now I'm enjoying getting stuck into it.
All I did was give Bilbo a nudge out of the door and Frodo a ring that I suspected could possibly be an ancient Ring of Power™ forged by the Dark Lord Sauron, into which he poured his cruelty, malice, and his will to dominate all life.
Fun fact: the s was added to island in the 16th century as a mistake because grammarians added an s to isle to make it look more like the Latin insula, even though there was no s sound in either island or isle.
So in Slavonic linguistics, there's a sound change known as the Slavic liquid metathesis, which is what gives us South Slavic forms like grad (town) as in Belgrad, as opposed to East Slavic forms, like gorod, as in Belgorod.
The reconstructed ancestor of gorod and grad is *gord (in historical linguistics, an asterisk indicates a reconstructed form). Due to changes in syllable boundary rules in the Slavic language of the day (roughly 8th/9th century AD), you could no longer have two consonants at the end of a syllable, so *gord had to change. In East Slavic, this was solved by adding an extra vowel to break up the consonant cluster, giving us gorod. In South and West Slavic, this was done by moving the /r/ sound to the onset (start) of the syllable (and the vowel was also changed), giving us grad. The "liquid" part of the name refers to "liquid" sounds, /r/ and /l/, since this particular process applied to them.
It almost looks like this is what's going on here, although not quite. It would have to be gulgulg > gluglug to count as liquid metathesis, but the l and u switched around, which is good enough for me. Plus there's the pun with liquid and water.
Hopefully that at least somewhat explains the joke. I don't know if it's very clear.
https://en.m.wiktionary.org/wiki/that