Using this Phoenician letter for just a vowel seem is due to the early Greek alphabets, which adopted the letter "omicron" to signify the vowel /o/. The letter was adopted with the value within the Previous Italic alphabets, including the early Latin alphabet. Spotify is unavailable on this browser. https://erickxfkpw.bloguerosa.com/36019184/facts-about-o-sapinho-e-a-borboleta-revealed