stˈʌdiz ˈɪndᵻkˌeɪt ðæt æz kˈɜːɹəntli dᵻfˈaɪnd, ɪt kəmpɹˈaɪzᵻz fˈoːɹ lˈɪnɪɪdʒᵻz: ðə "mˈoʊbəl" lˈɪnɪɪdʒ ɹˈeɪndʒɪŋ fɹʌmðə mˈoʊbəl ɹˈɪvɚ tə ðə baɪlˈɑːksi ɹˈɪvɚ, ðə "pˈɜːl" lˈɪnɪɪdʒ ɹˈeɪndʒɪŋ fɹʌmðə wˈʊlf ɹˈɪvɚ tə ðə pˈɜːl ɹˈɪvɚ, ðə "pˈɔnttʃɑːɹtɹˌeɪn" lˈɪnɪɪdʒ ɹˈeɪndʒɪŋ fɹʌmðə bˈaɪuː bˈɑːnfaʊkə ɪn luːˌiːzɪˈænə tə ðə blˈaɪnd ɹˈɪvɚ, ænd ðə "wˈɛstɚn" lˈɪnɪɪdʒ ɹˈeɪndʒɪŋ fɹʌmðə kˈælkɐsˌɪuː ɹˈɪvɚ tə ðə wˈɛst fˈɔːɹk ʌvðə sˌæn dʒæsˈɪntoʊ ɹˈɪvɚ.
Studies indicate that as currently defined, it comprises four lineages: the "Mobile" lineage (ranging from the Mobile River to the Biloxi River), the "Pearl" lineage (ranging from the Wolf River to the Pearl River), the "Pontchartrain" lineage (ranging from the Bayou Bonfouca in Louisiana to the Blind River), and the "Western" lineage (ranging from the Calcasieu River to the west fork of the San Jacinto River).