A verbal form of Ad. bêth “expression, saying, word” attested only as an agental-formation as part of the noun izindu-bêth “true-sayer” (SD/427); see that entry for further discussion of its phonetic development. As suggested by Thorsten Renk suggested (NBA/24, 26), the verb stem is probably bith-, consistent with its primitive root ✶Ad. √BITH. Since agental forms generally have a lengthened or fortified vowel, the verb stem bith- could have the fortified agental form -bêth.
References ✧ SD/427