1. A computer-implemented method of automatic speech recognition, comprising: obtaining, via at least one acoustic signal receiving unit, audio data including human speech; generating, via a decoder, a static vocabulary weighted finite state transducer (WFST) having nodes connected by arcs to propagate at least one token through the static vocabulary WFST and at least one dynamic vocabulary trigger marker at at least one of the arcs; propagating, via the decoder, a token through at least one dynamic vocabulary WFST upon the at least one token reaching the trigger marker; propagating, via the decoder, a token through at least one grammar WFST having at least one dynamic vocabulary class marker that indicates a type of dynamic vocabulary and is associated with the dynamic vocabulary of at least one of the dynamic vocabulary WFSTs with a propagating token; providing, via the decoder, a hypothetical word or phrase based at least in part on the obtained human speech and depending, at least in part, on the WFSTs and comprising terms in the static vocabulary, dynamic vocabulary, or both vocabularies; determining, via an interpretation engine, user intent based at least in part on output from the decoder based at least in part on the hypothetical word or phrase; and initiating, via the interpretation engine, a response or action based at least in part on the determined user intent, the initiated response or action being implemented via speech output from a speaker component, via visual output from display component, and/or via other action from one or more end devices.