8. A system of keyword recognition in a speech signal, the system comprising: one or more processors configured to: sample the speech signal in one or more frames; determine a first likelihood score of one or more features of a frame, of the one or more frames, of the speech signal being associated with one or more states in a first model, wherein the one or more states in the first model correspond to one or more tied triphone states of a keyword to be recognized in the speech signal, and wherein the one or more features comprise a frequency of an audio in the frame; determine a second likelihood score of the one or more features of the frame of the speech signal being associated with one or more states in a second model, wherein the one or more states in the second model correspond to one or more monophone states of the keyword to be recognized in the speech signal; determine a third likelihood score based on the first likelihood score and the second likelihood score, wherein the third likelihood score is deterministic of a likelihood of the frame corresponding to keywords other than the keyword; and determine a presence of the keyword in the speech signal based on the first likelihood score and the third likelihood score.
8. A system of keyword recognition in a speech signal, the system comprising: one or more processors configured to: sample the speech signal in one or more frames; determine a first likelihood score of one or more features of a frame, of the one or more frames, of the speech signal being associated with one or more states in a first model, wherein the one or more states in the first model correspond to one or more tied triphone states of a keyword to be recognized in the speech signal, and wherein the one or more features comprise a frequency of an audio in the frame; determine a second likelihood score of the one or more features of the frame of the speech signal being associated with one or more states in a second model, wherein the one or more states in the second model correspond to one or more monophone states of the keyword to be recognized in the speech signal; determine a third likelihood score based on the first likelihood score and the second likelihood score, wherein the third likelihood score is deterministic of a likelihood of the frame corresponding to keywords other than the keyword; and determine a presence of the keyword in the speech signal based on the first likelihood score and the third likelihood score. 13. The system of claim 8 , wherein the determination of the third likelihood score is based on a third model, wherein the third model comprises a garbage state.