Are prayers valid if I don't understand what the imam is reciting?

Like after reading surat al-fatiha you would then read another verse in every rak'ah but I don't know arabic, I am currently learning the 4 quls. So if I go to the masjid and the imam is reciting other verses in arabic then obviously I won't understand what they are saying. So do I just stay in silent during this time clueless to what is being said or should I recite a verse that I know while he is reading his own verse? And is there any point of me attending taraweeh prayer because I don't know arabic or the ayahs they readout?