Google ANDROID Quick Start Guide (4.4, KitKat) - Manual (Page 18)

ANDROID QUICK START GUIDE ESSENTIALS 14
IMPORTANT: To detect when you say “Ok Google” to
launch Voice Search or Voice Actions, Google analyses
sound picked up by your device’s microphone in intervals
of a few seconds or less. The sound is immediately
discarded after analysis and is not stored on the device or
sent to Google.
To see some examples of what you can tell Google to do, say or
type “help”.
Turn hotword detection on or off
The ability to trigger a search or action by saying “Ok Google” is
called hotword detection. To turn it off or on, open Google Now
or the Google app and touch Menu > Settings > Voice > Hotword
detection.
Voice Search
Spoken answers are supported for English only at this time.
After you touch the Microphone icon or say “Ok Google”, Google
listens as you speak and initiates the search or action that you
describe. If Voice Search doesn’t understand you, it lists some
suggestions. Just touch the one that you want.
If you ask Google a question by speaking, the answer may
be spoken back to you. The answer can be a fact, weather
condition, stock price, flight status, sports score, currency
conversion, mathematical calculation and more. Spoken
answers are turned on by default for Voice Search.
For examples and more details, visit Voice Search .