Many of the non-alphanumeric characters were positioned to correspond to their shifted position on typewriters; an important subtlety is that these were based on mechanical typewriters, not electric typewriters.
mˈɛnɪəv ðə nˈɑːnˌælfənuːmˈɛɹɪk kˈæɹɪktɚz wɜː pəzˈɪʃənd tə kˌɔːɹɪspˈɑːnd tə ðɛɹ ʃˈɪftᵻd pəzˈɪʃən ˌɔn tˈaɪpɹaɪɾɚz; ɐn ɪmpˈoːɹtənt sˈʌɾəlɾi ɪz ðæt ðiːz wɜː bˈeɪst ˌɔn mᵻkˈænɪkəl tˈaɪpɹaɪɾɚz, nˌɑːt ᵻlˈɛktɹɪk tˈaɪpɹaɪɾɚz.