Selamat datang, Doni!
Yes, you can cast the spells in your language. However, most books about Wicca will be in English, and the tradition of Wicca is very Western. I also live in Southeast Asia, so I feel that an "earth-based" or "land-based" religion such as Wicca is too different for the tropical region of the world. So, it is not only the language, but the custom and the culture.
For example, I still believe in the Fae, which is Western, but to me the Fae are the same as the local "folkloric" beings. I do not meet with any Leprechaun, but I do meet with a Patianak. The Patianak is the same as a Fae in my opinion, or any of the Japanese Yokai (same as Fae.) Other people can disagree.
Indonesia has local traditions of magic, yes? Belief in the gamelan is maybe part of local tradition. It is not necessary for all magic to be from Europe or America.
This is not to discourage you. This is only my point of view. If you have this interest, then you feel free to read and communicate with others about the Wicca world!