system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do voice recognition applications like Siri know what we're saying?
gpt
First, it cuts the voice recording into really small segments, like 2/100 or 1/100 of a second long. Then, it multiplies each segment by a bell function to get a clear waveform in the middle with reduced interference from neighbouring samples. The waveform of each segment is analysed and compared to waveforms of known sounds. That way, you know which sound was being pronounced during each segment. Remove repeating sounds and you have a basic phonetic spelling of the pronounced phrase. Now you just need some process to match it to a dictionary of known words/phrases, and turn the phonetic spelling into real words.