This post is about what I experienced when I talked to foreigners in bahasa Indonesia. Many of them said that bahasa Indonesia is quite easy to learn. However, in my personal point of view, it is rather difficult since there are so many grammar rules that are acceptable but unexplainable.
2 Sounds of Letter 'e'
Bahasa Indonesia actually has only one letter 'e'. But in fact, it has 2 sounds for that letter. The first sound of letter 'e' sounds like 'red' and the second sounds as you pronounce word 'bird'.
Many foreigners only recognize the first type of 'e' when speaking bahasa Indonesia. Although it is acceptable, but it would probably sound little bit funny. If you speak with random guys in Indonesia, they will fix your pronunciation.
Learn The Language Means Learn The Accent
Again, this error is still acceptable. That learn any language means learn the accent, or, at least being so close to the native accent. This is what English teachers taught in English class. For many foreigners, they still use their accent in speaking bahasa Indonesia. Although intonation does not really influence they messages one wants to deliver in a conversation, but it is better to be noticed.
Vibration Sound of Letter 'r'
Letter 'r' in bahasa Indonesia is pronounced totally different with how it is pronounced in English. Indonesians stress it by vibrating their tongue while many foreigners do not. However, Indonesians recognize that un-vibrated sound of letter 'r' is fair if it is spoken by foreigners.