19. The non-transitory computer-readable medium of claim 15 , wherein selecting the shortest segment among the plurality of segments in the first audio signal that have voice activity comprises determining a lowest number of contiguous frames in the received audio signal that comprise the accept enrollment flag.
20. The non-transitory computer-readable medium of claim 19 , wherein the operations further comprise: comparing the number of frames in the sequence of contiguous frames corresponding to the shortest segment to the threshold value, the threshold value comprising a threshold frame value; and when the number of frames in the sequence of contiguous frames corresponding to the shortest segment is less than the threshold frame value, prompting the user to speak the trigger phrase in a second attempt.