haʊˈɛvɚ, ˈiːvən nˈætʃɚɹəl sˈɪstəmz sˈʌtʃ ɐz ˈækɑːl fˈaɪnd əkˈeɪʒənəl nˈiːd tə ɹᵻzˈɔːɹt tʊ ˌɑːɹɾɪfˈɪʃəl mˈiːnz kˈɔːld kənvˈɛnʃənz.
However, even natural systems such as Acol find occasional need to resort to artificial means called conventions.