He wanted to localize the difference between man and the other animals, which appeared to reside in speech.
hiː wˈɔntᵻd tə lˈoʊkəlˌaɪz ðə dˈɪfɹəns bᵻtwˌiːn mˈæn ænd ðɪ ˈʌðɚɹ ˈænɪməlz, wˌɪtʃ ɐpˈɪɹd tə ɹᵻsˈaɪd ɪn spˈiːtʃ.