1. A method implemented by one or more computing devices, the method comprising: identifying features of sound data from a plurality of recordings; calculating values for individual frames of the sound data from the plurality of recordings, each of the values based on a similarity value scaled by a priority value, wherein: the similarity value corresponds to a similarity determined using a similarity matrix built by comparing a first set of individual frames of a first of the plurality of recordings to a second set of individual frames of a second of the plurality of recordings, wherein the similarity matrix represents a comparison between the first set of individual frames and the second set of individual frames computed using a normalized inner product of compared frames; and the priority value assigned to individual frames of the sound data based on the identified features of the sound data as the identified features occur in the respective individual frames of the sound data, the priority value based on how speech characteristics of a particular frame compare to speech characteristics of other individual frames of the sound data; and aligning the sound data from the plurality of recordings based at least in part on the calculated values that are based on the similarity value scaled by the priority value, wherein individual frames of the sound data from the plurality of recordings are more likely to be aligned between different recordings when the priority value assigned to the individual frames of the sound data based on the identified features is higher than priority values assigned to other individual frames; and outputting the aligned sound data.