Viterbi Algorithm

The Viterbi algorithm is a dynamic-programming procedure for finding the most likely sequence of hidden states in a Hidden Markov Model given a sequence of observations. It is the standard solution to part-of-speech tagging, many speech-recognition tasks, and decoding problems in communications. In accessibility technology, the Viterbi algorithm appears in speech-recognition engines that power voice-input systems, in part-of-speech-aware predictive text and AAC word-prediction systems, and in gesture-recognition pipelines for sign-language or touchless interfaces. Though neural sequence models have largely replaced it in state-of-the-art systems, Viterbi remains pedagogically central and still appears in resource-constrained or embedded accessibility devices.