So, just for clarification, "du" is you for a singular person. Whereas "ni" is you for a group of people (but is not "they")?
So in Swedish "You drink milk" and "You are drinking milk" is one and the same? There's no way to differentiate between these statements?
Can this be said as a question as well? With the right emphasis it can be received the same as "Do you drink milk?".
No, but with the right emphasis it can be made into a question the same way You drink milk? can be a question in English. To make a real question such as Do you drink milk? is in English, you need to put the verb first and say Dricker du mjölk?.
When all you hear is the audio... it's not easy to distinguish De, from Du, from Vi, although I can usually hear the last one... the other two.. it's flip a coin.
So how can you determine the past, present, and future tense of verbs in Swedish?
They'll get there. But here's a preview:
For the verb "to be": Jag är = I am / jag var = I was / Jag ska vara = I will be
For the verb "to speak": Jag pratar = I speak / jag pratade = I spoke / Jag ska prata = I will speak
(There are other ways of expressing the plural, such as with the verb "kommer" instead of "ska", or just using present tense forms and letting the future tense be implied by context.)