no need to use 'dan' it should be aku mau bicara bahasa Indonesia

well, do you mean "i want speak indonesian and understand you"? Aku mau bicara bahasa indonesia dan mengerti kamu.

Kalau kamu mau aku mau kok mengajari kamu bahasa Indonesia yang baik dan benar... (If U want I can teaching you Indonesian language with well)

Yes, take out the first 'dan'. I think you could also use "berbahasa" as the verb? (bahasa=language, berbahasa=to speak a language).

Hello, I am cynthia, I saw your brief details and decided to write you. I want to make a good friendship.I Feel we shall make a better introduction in our next communication. contact me through my email address ([email protected] ) for more details and my pictures. I will like to know you better for more personal information, please do not write me on this site because i do not visit the site all the time..kindly reply me with ([email protected] )i am waiting . Thanks