Coptic is the only stage written alphabetically to show vowels, whereas Egyptian was previously written in Egyptian hieroglyphs, which only represent consonants.
kˈɑːptɪk ɪz ðɪ ˈoʊnli stˈeɪdʒ ɹˈɪʔn̩ ˌælfəbˈɛɾɪkli tə ʃˈoʊ vˈaʊəlz, wˈɛɹæz ɪdʒˈɪpʃən wʌz pɹˈiːviəsli ɹˈɪʔn̩ ɪn ɪdʒˈɪpʃən hˈaɪɚɹəɡlˌɪfz, wˌɪtʃ ˈoʊnli ɹˌɛpɹᵻzˈɛnt kˈɑːnsənənts.