Simon looks fairly easy to get working by itself but looks more difficult to integrate into your robotics framework
Julius is designed for Japanese though basic english support is available
This voice recognition system is based on CMU Sphinx2, however it has been optimized for speed and small devices.
This is an opensource project to develop acoustic models for speech recognition based on user contributed audio files. Several audio models are available for download.
Dedicating a page to the Pixhawk
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