There are six pure vowel sounds: a (as in English father), e (as in pay), i (as in me), o (as in go), u (as in do), the schwa (as in putt) which is also spelled e; and three diphthongs (ai, au, oi). The consonantic phonemes are rendered by the letters p, b, t, d, k, g, c ([tS/t?], like the ch in cheese), j ([dZ/d?] as in English), h, ng (which also occurs initially), ny (as in canyon), m, n, s (unvoiced, as in sun or cats), w, l, r (trilled or flapped) and y. There are five more consonants that only appear in loanwords: f, v, sy (pronounced sh), z and kh (as in loch).
In the guide to vowel sounds above, note that the pronunciation of English words assumes an American accent, and is an approximation. Vowel sounds in Indonesian are short and clear. For British and Australian people, use the following guide: a (as in English hut), e (as in pet), i (as in hip), o (as in top), u (as in put), the schwa (as in the e in taken) which is also spelled e; and three diphthongs (ai as in bike, au as in how, oi as in boy).
Here are a few useful tips:
~ Indonesian pronunciation is similar in many ways to Italian. If
you are completely new to Indonesian and are at all familiar with Italian
pronunciation, it may help to think of how Italians pronounce certain
words such as pasta or Napoli.
~ However, in Indonesian, the g is always hard as in got, never soft as in giraffe.
~ Indonesian is pronounced with the tongue further forward in the mouth than in English.
~ k, p, and t are unaspirated, ie they are not followed by a noticeable puff of air as they often are in English words.
~ The t is pronounced with the tongue forward, against the back of the top teeth, (halfway between the English "t" and "th" sounds). For the letter d, the tongue position is the same as in the English d. This is not essential for the learner of Indonesian, but it will help to distinguish t from d, which are otherwise almost identical.
~ The glottal stop: When k is at the end of a word, the sound is cut off sharply (a "glottal stop"), e.g. "baik", "bapak". This is similar to some British (esp. London) accents where the final t is dropped ("got", "what"). A few Indonesian words have this sound in the middle, e.g. "bakso" (meatballs), or represented by an apostrophe in Arabic derived words such as "Al Qur'an".
~ The accent is placed on the second-last syllable of each word.