1. A method performed by at least one computer processor executing computer program instructions stored on at least one non-transitory computer-readable medium, the method comprising: (A) using a language model to decode, by a speech decoder executed by the at least one computer processor, a first portion of an audio signal into a first word in a token stream; (B) after (A): (B)(1) select a punctuation mark based on the language model and the first word; and (B)(2) inserting, by the speech decoder, the punctuation mark into the token stream at a position after the first word, based on a lexical cue provided by the first word; and (C) after (B), using the language model, the punctuation mark, and the first word to decode, by the speech decoder, a second portion of the audio signal into a second word in the token stream at a position after the punctuation mark.
9. The method of claim 1 , further comprising: (D) before (A), training the language model using a document corpus, wherein the document corpus includes words and punctuation.