James P. Allen has demonstrated that slightly different rules apply to Egyptian: for instance, Egyptian allows two identical consonants in some roots, and disallows velars from occurring with pharyngeals.
dʒˈeɪmz pˈiː. ˈælən hɐz dˈɛmənstɹˌeɪɾᵻd ðæt slˈaɪtli dˈɪfɹənt ɹˈuːlz ɐplˈaɪ tʊ ɪdʒˈɪpʃən: fɔːɹ ˈɪnstəns, ɪdʒˈɪpʃən ɐlˈaʊz tˈuː aɪdˈɛntɪkəl kˈɑːnsənənts ɪn sˌʌm ɹˈuːts, ænd dˌɪsɐlˈaʊz vˈɛlɚz fɹʌm əkˈɜːɹɪŋ wɪð fˈɑːɹɹɪndʒˌiəlz.