"potřebujou" is only dialects, grammatically right is "potřebují"! Do not teach foreigners bad Czech!
Check with the Czech academy of science, Department of Czech. They do not agree with you
When do I use potřebují versus potřebujou for "they need"?
It's the same with (já) potřebuji / potřebuju
-u/-ou are considered more colloquial, -i/-í more formal.
So both "I need" and "they need" use potřebujou?
potřebuji/potřebuju = 'I need'
potřebují/potřebujou = 'they need'
Sorry, I made a typo. Edited now.
It is very hard to me to tell the difference in the sound of "Potřebuju" and "Potřebujou" it would be really nice and helpful if someone could explain the difference to me a bit :)
It's literally "Ou" the "O" is audible, like English "low" with the "-w" extended out to a "lowoo." Czech „-u” sounds like the "ou" in English "you"
after reading the other comments. is Potrebuju wrong?
yes, that is first person singular (I need/já potřebuju).