I found a reddit post why sodium and potassium have 2 names:
There was some argument over what to call the elements. They were discovered by Sir Humphrey Davy who called them "sodium" from the Latin "sodanum" for a compound of sodium used as a treatment for headaches, and "potassium" from English "potash" which was the method used to extract potassium salts.
But a German chemist, Ludwig Wilhelm Gilbert, proposed "natronium" from Neo-Latin as a reference to "natron" which is what the Egyptians called sodium carbonate, and "kalium" from the Neo-Latin of the Arabic "al qalyah" which means "ashes".
So in English they were "sodium" and "potassium", but in German they were "Natronium" (now simply "Natrium") and "Kalium".
It just so happened that the guy who invented the modern chemical symbols was Jöns Jacob Berzelius. He was Swiss and spoke German, so he derived the symbols from the German names.
Switzerland and Sweden aren't the same country? Well God damnit, there goes my dream vacation of visiting the home of Ikea and chocolate.
Wait, now which one of them am I supposed to refer to as Swaziland?
There are also Sn (Stannous) for Tin, Pb (Plumbum) for Lead, Fe (Ferrum) for Iron, Hg (Hydrargyrum) for Mercury, Au (Aurum) for Gold and Ag (Argentum) for Silver.
That's almost as much fun as Davy pointlessly waffling between alumium, aluminum, and aluminium till we once again ended up with people who speak the same language using different terms.
And pot=pot, so potassium is 'from the ashpot' which was how kalium salts were extracted, by adding water to wood ash, then filtering and evaporating the water off.