from the Sirius site:

Sirius is an open end-to-end standalone speech and vision based intelligent personal assistant (IPA) service similar to Apple’s Siri, Google’s Google Now, Microsoft’s Cortana, and Amazon’s Echo. Sirius implements the core functionalities of an IPA including speech recognition, image matching, natural language processing and a question-and-answer system.

It can be run using Sphinx (sphinxbase and pocketsphinx) or Kaldi.

check it out on GitHub