As for the Germanic languages http://www.myetymology.com/german/kaufen.html
I had a look into the etymological dictionary of Czech by Rejzek and found that Proto-Slavic *kupiti was an old loanword from Germanic *kaupjan which proceeded from Latin "caupō" (of uncertain origin) meaning "shopkeeper". The Latin word came to the Germanic peoples perhaps from the Roman soldiers on the Rhine around 100 AD.
And in fact the English word cheap, which once used to be part of the expression good cheap, like the Dutch goedkoep or French bon marché (not a cognate obviously but a similar meaning) so the expression meant a good buy or a bargain
This reminds me of the English word confetti (meaning small pieces of streamers or paper, which are usually thrown at parades, sporting team winners, and celebrations, especially weddings) the origins are from the Latin confectum, with confetti the plural of Italian confetto, small sweet. https://en.wikipedia.org/wiki/Confetti
it is OCCIDENTAL Indo-European which belongs to the CENTUM group( pronounced KENTUM) meaning 100 in Latin. . ALL European languages with the exception of Finnish- Estonian - Hungarian- Basque- Georgian and Turc are Indo-European languages divided into 3 big groups : SLAV - GERMANIC - LATIN, Greek and Armenian being isolated (not belonging to any of those 3 groups.) The ORIENTAL Indo-European languages of today are : HINDI/HINDUSTANI- plus many of the other languages from INDIA ( Bengali, Gujarati etc) FARSI from Afghanistan- IRANIAN - NEPALI - CINGHALESE - URDU from Pakistan - TADJIK from Tadjikistan ( which is the only remaining Indo-European language of Central Asia)The ORIENTAL INDO-EUROPEAN LANGUAGES BELONG TO THE "SATEM" GROUP ( 100 in SANSCRIT) Indo-European languages are - by far - the most widely spoken languages of this world
Not really. Vikings (the Русь) arrived into the Kiev and Novgorod lands and rose to princely status, ruling over the local East Slavic population and eventually assimilated and "Slavicized." There were no such people or languages as Russian or Ukrainian, yet. They spoke an Old East Slavonic. Киевская Русь became a powerful empire but was destroyed by the Mongols centuries before Slavic princes came to prominence in the northeastern, now-Russian lands. They still submitted to Mongol khans and chieftains, and a lot of their political structure was influenced by nomadic Mongol brutal rule--different from the merchant Kiev Русь political structure. Scholars disagree about the history of Alexander Nevskiy, Batu Khan, and the lineage of modern Russians from Киевской Руси. Until Peter the Great appropriated the terms "Россия" and "русские," the land was Московия and the people московиты. The original Русь people by that time were already under Lithuanian-Polish rule completely culturally isolated and having nothing to do with the Muscovites.
"покупать" is the imperfective aspect and "купи́ть" is the perfective aspect. And "купи́ть" is used because the action was completed i.e, the buying of the chocolate was actually done. The imperfective aspect usually refers to - incomplete, ongoing, habitual, reversed or repeated actions. more here
True, "купи́ть" does not have a present tense conjugation but it has an imperative (command) form [Купи/Купите] that is used here.
Sorry, can you explain a little more @wizwisdom? You say "купи́ть is used because the action was completed i.e, the buying of the chocolate was actually done" - but it seems to me that someone is being instructed in the present to take an action in the imminent future - the buying has not been done (in the past), and it may never be!
So is the perfective aspect the usual aspect for the imperative - whatever the logic?
Он покупает новую одежду когда старая грязная. He buys new clothes when the old ones are dirty. Он сейчас покупает одежду. He is buying clothes now. Он купит одежду. He will buy clothes. Он купил одежду. He bought clothes. Он покупал одежду но передумал. He was buying clothes but changed his mind.
Yes, it is accusative plural. But it sounds (and writes) equal as nominative plural. So only by form here you can't tell if it is nominative or accusative. For people who start study other languages knowing only English or French, it is harder to feel.
But you can catch the difference if you think about the:
they (nom.) and them (acc.).
(I-me; he-him; she-her; we-us or if you know the archaic thou (nom.) -thee (acc.) - thy (gen.))
So let's try to ask back:
Купи конфеты, пожалуйста.
Which is a correct question?
Shall I buy they? (nom.) :(((
Shall I buy them? (acc.) :)))
This way you can feel that this was obviously accusative.