Why do many Oceanic languages end words with vowels?

In most Oceanic languages, the tendency for all words to end in a vowel is the result of specific historical phonological changes. This outcome is typically driven by one of two processes:

• Loss of final consonants: Some languages, such as Fijian and various Polynesian languages, developed open final syllables through the historical disappearance of consonants that previously occupied the end of words.1
• Addition of supporting vowels: Other languages, such as Malagasy and Mussau, achieved open final syllables by adding either an "echo" vowel or an invariant "supporting" vowel to the end of words that would otherwise have ended in a consonant.1

These developments reflect a broader structural preference within many Austronesian languages for CVCV (consonant-vowel-consonant-vowel) sequences, which helps maintain a preferred canonical shape for words.1