Abstract: In one aspect, an audio playback device having at least one microphone captures a voice input. The playback device detects, within the voice input, at least one keyword from among a plurality of command keywords supported by the playback device. The playback device determines, via a local natural language unit (NLU), an intent based on the keyword. The keyword is then evaluated based at least in part on a volume characteristic of the voice input. Based on the evaluation, the playback device either forgoes further processing of the voice input or performs a command in accordance with the determined intent.