The Indonesian term for “alphabet” is abjad, and for “letter (of the alphabet)”huruf. Both these words are borrowed from Arabic. Just as the English word “alphabet” derives from the first two letters of the Greek alphabet (alpha andbeta), so too the Arabic term abjad is a snapshot of the first four letters of the Arabic alphabet (ā b t t j h h d d). And just as the English words “letter” and “literally” are etymologically related (both ultimately descended from the Latinlitera), so too in Indonesian the words huruf (letter) and harfiah or harafiah(literally) are derived from the same Arabic root: h-r-f.
The Indonesian alphabet, with its combination of Arabic terminology and European letters that are pronounced Dutch-style, preserves a memory of the history of literacy in Indonesia. With the arrival of Islam the Arabic abjad became widely used in the islands of Indonesia, but during the era of Dutch colonial rule it was almost wholly displaced in everyday life by the Western European alphabet inherited from the Roman empire.
It is still quite common to hear variant pronunciations of the letters of theabjad. For example, the letter C is still quite often pronounced like “say” as it used to be before the spelling reform of 1972. In Module 3 of The Indonesian Way you met the term WC (a toilet) which is still widely pronounced “way say” rather than “way chay” (although the latter pronunciation is sometimes heard too). Similarly the term AC(airconditioning) is usually pronounced “ah say”. Sometimes too you hear people use “ee grek” for the letter Y and “koo” for the letter Q. But these are exceptions for noting only. Apart from saying “way say” and “ah say” you probably won’t need to practise using them.