"She speaks English and Polish."
Translation:Ona mówi po angielsku i po polsku.
Is the po compulsory for both items? How would that work for a longer list?
no, I think it's not compulsory, but it sounds better to me, but only for two adjectives.
So I'd say
Ona mówi po polsku i (po) angielsku
Ona mówi po polsku, angielsku, hiszpańsku i (po) niemiecku.
mowi or mowie or mowize or mowicie or mowisz can anyone explain the function of these words as I cannot seem to grasp the context.
Singular: 1. Ja mówię 2. Ty mówisz 3. On/ ona/ono mówi. Plurar: 1 my mówimy 2. Wy mówicie 3. Oni/one mówią.
It appears to be the default translation. You still can often use "know" and "speak" interchangeably when you mean languages.
In this sentence you should consider "po polsku" and "po angielsku" as fixed phrases without real meaning of 'po'.
It can be understood as 'Polish-style", "English-style", Apart from talking about languages, they can be used in names of dishes, like "ryba po grecku" (Greek-style fish).