20. The system of claim 11 , wherein: at least one of the one or more first feature units or at least one of the one or more second feature units includes a single-word feature unit, the single-word feature unit being associated with a single-word feature template including a word satisfying a predetermined relative-position relationship with a present reference position and one or more semantic features of the word; the identification module is further configured to: select a position of another word as the present reference position; determine the word satisfying the predetermined relative-position relationship with the present reference position; and identify the single-word feature unit based on at least: the one or more semantic features, the single-word feature unit, and the predetermined relative-position relationship between the word and the present reference position.
11. A system for modifying a voice file comprising a plurality of words, the system comprising: a silence-detection module configured to detect silences in the voice file and to divide the voice file into multiple segments based on at least the detected silences, an identification module configured to: apply a language model to the voice file as a whole, the language model including a plurality of feature units, a preliminary punctuation state, and a preliminary weight of the preliminary punctuation state, each of the feature units including a word or phrase, a part of speech or sentence element of the word or phrase, the application of the language model to the voice file as a whole identifying in the voice file as a whole one or more first feature units of the plurality of feature units; and identifying in the segments one or more second feature units of the plurality of feature units; and a punctuation-addition module configured to: generate a first aggregate weight R1 based on a combination of the preliminary weights of the preliminary punctuation states corresponding to the identified one or more first feature units; apply the language model to the segments, the application of the language model to the segments to generate a second aggregate weight R2 including a combination of the preliminary weights of the preliminary punctuation states corresponding to the identified one or more second feature units; generate a third aggregate weight R3 determined according to R3=a×R1+(1−a)×R2 where 0<a<1; and modifying the voice file so as to include one or more final punctuations based on at least the third aggregate weight R3.