one lil question

Hello people i am new to this part of Kmc but i would like to know ... when i finished watching ROTJ last nite my sister asked me a rather puzzling question ... C3po is a translator and can speak numberous languages but she noticed that he translates wat people say for English speaking but he doesn't translant wat they say for the forgien people like jabba the hut ... or the ewoks he translates wat they say for hans and luke but when luke or hans speak ts like they already know what they have sed ... pologise for the way i have put it didnt know how to

the idea is that they don't speak english, but Basic, a language that most of the people should/can speak (like Jabba)

and he does translate into ewok btw

Huttese is translated because, like many localised languages' (Welsh, for example), it is spoken by those who understand the majority language. For example, Jabba speaks Huttese but he can understand "English" perfectly well. We saw this typified in episodes 1 & 2 with Watto speaking Huttese but quickly switching to "English" for the 'outlanders'.

you also saw it in ROTJ 😉
and Ewokese