1. A method for adjustment of temporal acoustical characteristics of words in an item structure, the method comprising: receiving the item structure comprising at least a first item, the first item representing a first set of one or more words; determining a number of speeds of audio playback for the item structure; determining, in response to the number of speeds of audio playback for the item structure, a representation of the item structure for each of the number of speeds of audio playback by determining at least a first abbreviated item for one of the number of speeds comprising: extracting one or more keywords or phonemes from the first set to generate a first keyword item; abbreviating the keyword item by generating a first alternative representation for the first keyword item to create a first abbreviated item; and storing the first abbreviated item; wherein abbreviated items for a faster speed are shorter than abbreviated items for a slower speed by extracting less keywords or phonemes from the first set for the faster speed, generating a shorter alternative representation for the faster speed, or both.