Mistakes made by those who learn English as a second language is probably the lack of English vocabulary,understanding grammar or word order. You will become a better speaker when you understand grammar better and develop good vocabulary but then you may make mistakes because of idioms, commonly used phrases and direct translation from Bahasa to English.
Jadi, belajarlah vocabulary, grammar,word order, idioms and commonly used phrases :)
Try to find the mistake and make correction.
1.Do you know where is the rest room?
2.I joined a meeting yesterday.
3.We are making more money this year.
4.The money is not enough.