This allows UTF-8 to be backward compatible with 7-bit ASCII, as a UTF-8 file containing only ASCII characters is identical to an ASCII file containing the same sequence of characters.
ðɪs ɐlˈaʊz jˌuːtˌiːˈɛf ˈeɪt təbi bˈækwɚd kəmpˈæɾᵻbəl wɪð sˈɛvənbˈɪt ˈæski, æz ɐ jˌuːtˌiːˈɛf ˈeɪt fˈaɪl kəntˈeɪnɪŋ ˈoʊnli ˈæski kˈæɹɪktɚz ɪz aɪdˈɛntɪkəl tʊ ɐn ˈæski fˈaɪl kəntˈeɪnɪŋ ðə sˈeɪm sˈiːkwəns ʌv kˈæɹɪktɚz.