"... Some of the beings in Leviticus 11:13–19 and Deuteronomy 14:12–18 can no longer be identified with any certainty. The various targumists disagreed about the meaning of some names and did not know the identity of others. The rabbis had the same difficulty in the Babylonian Talmud, Chullin 63a–b. The Tosaphot to this discussion also questions the rabbinical translations. Onkelos omits the accusative et, which is yat in Aramaic, three times each in verses 13, 16, 17, 18, and 19, and twice in verse 14. This is another of many proofs that our targumist followed the method of Rabbi Ishmael, who interpreted Scripture according to its plain meaning and who said, “The Torah speaks in human language,” and not Rabbi Akiva who insisted that every letter and word of the Torah, including et, has meaning. Nachmanides points out that only those birds mentioned in the Torah are prohibited because Scripture does not mention specific characteristics in birds that render them unclean as it does with animals and fish. Nachmanides suggests that the specified birds are proscribed because they display cruelty and when they are ingested they harm the human spirit ..."