Voice assistants like the ones built into phones and smart speakers combine several distinct AI systems working together in sequence, all happening quickly enough to feel like a natural, instant conversation.
Step 1: Wake Word Detection
A small, efficient model constantly listens for a specific wake phrase, running locally on the device to avoid sending all audio to the cloud continuously. Once the wake word is detected, the device begins actively recording and processing the following speech.
Step 2: Speech to Text
The recorded audio is converted into written text using an automatic speech recognition model, which has been trained on huge volumes of spoken audio paired with its correct transcription across many accents and speaking styles.
Step 3: Understanding the Request
The transcribed text is then passed to a natural language understanding system that identifies the intent behind the request, such as setting a timer or checking the weather, along with any relevant details like a specific time or location.
Step 4: Generating a Spoken Reply
Once the assistant determines the appropriate response, a text-to-speech system converts the reply back into natural-sounding audio, completing the loop from spoken request to spoken answer, often in under a second.