This theory has been criticized by some, such as Andrzej Zaborski and Alan Kaye, as being too many extensions to be realistic, though Zygmont Frajzyngier and Erin Shay note that some Chadic languages have as many as twelve extensions.
ðɪs θˈiəɹi hˈæzbiːn kɹˈɪɾɪsˌaɪzd baɪ sˌʌm, sˈʌtʃ ɐz ˈændəzˌɛdʒ zæbˈoːɹski ænd ˈælən kˈeɪ, æz bˌiːɪŋ tˈuː mɛni ɛkstˈɛnʃənz təbi ɹiːəlˈɪstɪk, ðˌoʊ zˈɪɡmɔnt fɹˈædʒzɪŋiɚ ænd ˈɛɹɪn ʃˈeɪ nˈoʊt ðæt sˌʌm tʃˈædɪk lˈæŋɡwɪdʒᵻz hæv æz mˈɛni æz twˈɛlv ɛkstˈɛnʃənz.