Comparative study of Afroasiatic is hindered by the massive disparities in textual attestation between its branches: while the Semitic and Egyptian branches are attested in writing as early as the fourth millennium BC, Berber, Cushitic, and Omotic languages were often not recorded until the 19th or 20th centuries.
kəmpˈæɹətˌɪv stˈʌdi ʌv ˌæfɹoʊˌeɪsɪˈæɾɪk ɪz hˈɪndɚd baɪ ðə mˈæsɪv dɪspˈæɹᵻɾiz ɪn tˈɛkstʃuːəl ɐɾɪstˈeɪʃən bᵻtwˌiːn ɪts bɹˈæntʃᵻz: wˌaɪl ðə sɛmˈɪɾɪk ænd ɪdʒˈɪpʃən bɹˈæntʃᵻz ɑːɹ ɐtˈɛstᵻd ɪn ɹˈaɪɾɪŋ æz ˈɜːli æz ðə fˈoːɹθ mɪlˈɛniəm bˌiːsˈiː, bˈɜːbɚ, kʊʃˈɪɾɪk, ænd ɑːmˈɑːɾɪk lˈæŋɡwɪdʒᵻz wɜːɹ ˈɔfən nˌɑːt ɹᵻkˈoːɹdᵻd ʌntˈɪl ðə nˈaɪntiːnθ ɔːɹ twˈɛntiəθ sˈɛntʃɚɹiz.