In Indonesian, there is a vocabulary formed from diphthongs and a combination of vowels. Before discussing further, we first understand what a diphthong is and what a vowel is. A diphtograph is a combination of two vowels in one syllable. While the combination of vowels contained in one word, but the placement of the syllables is different. Diphthongs in Indonesian are: ai, au, ei, oi. Examples of words with diphthongs: ai : pandai (pan-dai) - [Clever] au : harimai (ha-ri-mau) - [Tiger] oi : boikot (boi-kot) - [Boycott] ei : survei (sur-vei) - [Survey] Examples of words with combined vowels: Maaf : Ma-af [Sory] Pekerjaan : Pe-ker-ja-an [Occupation] So we can see the difference between a combination of vowels and diphthongs.