In the Coptic period, there is evidence for six major dialects, which presumably existed previously but are obscured by pre-Coptic writing; additionally, Middle Egyptian appears to be based on a different dialect than Old Egyptian, which in turn shows dialectal similarities to Late Egyptian.
ɪnðə kˈɑːptɪk pˈiəɹɪəd, ðɛɹ ɪz ˈɛvɪdəns fɔːɹ sˈɪks mˈeɪdʒɚ dˈaɪəlɛkts, wˌɪtʃ pɹɪzˈuːməbli ɛɡzˈɪstᵻd pɹˈiːviəsli bˌʌt ɑːɹ əbskjˈʊɹd baɪ pɹˈiːkˈɑːptɪk ɹˈaɪɾɪŋ; ɐdˈɪʃənəli, mˈɪdəl ɪdʒˈɪpʃən ɐpˈɪɹz təbi bˈeɪst ˌɔn ɐ dˈɪfɹənt dˈaɪəlɛkt ðɐn ˈoʊld ɪdʒˈɪpʃən, wˌɪtʃ ɪn tˈɜːn ʃˈoʊz dˈaɪəlɛktəl sˌɪmɪlˈæɹᵻɾiz tə lˈeɪt ɪdʒˈɪpʃən.