Artificial intelligent assistant

inaudibly

inaudibly, adv.
  (ɪnˈɔːdɪblɪ)
  [f. prec. + -ly2.]
  In an inaudible manner, so as not to be heard.

1798 Wordsw. P. Bell iii. li, He Sets down his hoofs inaudibly. a 1822 Shelley Summer Even. 24 Its awful hush is felt inaudibly.

Oxford English Dictionary

yu7NTAkq2jTfdvEzudIdQgChiKuccveC cb9f18cc8b0f09a4a2e84b553690dceb