replace Indonesian language in: agreements, information regarding goods / services, scientific papers, information through mass media, geographical names, public signs, road signs, public facilities, banners, and other information of public services in public area. While there are no sanctions of the uses of other languages, in Indonesian court's point of view, any agreements made in Indonesia but not drafted in Indonesian language, is null and void. In any different interpretations in dual-language agreements setting, Indonesian language shall prevail. Phonology Vowels It is usually said that there are six vowels in Indonesian. These six vowels are shown in the table below. However, other analyses set up a system with other vowels, particularly the open-mid vowels and . In standard Indonesian orthography, the Latin alphabet is used, and five vowels are distinguished: a, i, u, e, o. In materials for learners, the mid-front vowel /e/ is sometimes represented with a diacritic as ⟨é⟩ to distinguish it from the mid-central vowel ⟨ê⟩ /ə/. Indonesian has distinguished ⟨é⟩ [] and ⟨è⟩ [] since 2015, while Standard Malay has rendered both of them as ⟨é⟩. Poedjosoedarmo argued the split of the front mid vowels in Indonesian is due to Javanese influence which exhibits a difference between ⟨i⟩ [], ⟨é⟩ [] and è []. Another example of Javanese influence in Indonesian is the split of back mid vowels into two allophones of [] and []. These splits (and loanwords) increase instances of doublets in Indonesian, such as ⟨satai⟩ and ⟨saté⟩. Javanese words adopted into Indonesian have greatly increased the frequency of Indonesian ⟨é⟩ and ⟨o⟩. High vowels (⟨i⟩, ⟨u⟩) could not appear in a final syllable in traditional Malay if a mid-vowel (⟨e⟩, ⟨o⟩) happened in the previous syllable, and mid-vowels could not occur in the final syllable if a high vowel was present in the second-to-last syllable. Traditional Malay does not allow the mid-central schwa vowel to occur in consonant open or closed word-final syllables. The schwa vowel was introduced in closed syllables under the influence of Javanese and Jakarta Malay, but Dutch borrowings made it more acceptable. Although Alisjahbana argued against it, insisting on writing ⟨a⟩ instead of an ⟨ê⟩ in final syllables such as koda (vs kodə 'code') and nasionalisma (vs nasionalismə 'nationalism'), he was unsuccessful. This spelling convention was instead survived in Balinese orthography. Diphthongs Indonesian has four diphthong phonemes only in open syllables. They are: : kedai ('shop'), pandai ('clever') :