Duas soluções foram consideradas para o Ubuntu Touch: Pocket Sphinx e Julius . No entanto, o Pocket Sphinx parece ser a opção de longo prazo para o Ubuntu.
We built the voice feature around two different Open Source voice engines: Pocket Sphinx and Julius. While we started with Pocket Sphinx we weren't entirely happy with it's performance, and found Julius to start faster and provide better results. Unfortunately Julius is licensed with the 4-clause BSD license, putting it in multiverse and making it so that we can't link to it in the Ubuntu archive version of HUD. We're looking at ways to make it so that people who do want to install it from multiverse can easily use Julius, but what we'd really like is to make the Pocket Sphinx support really great. It's something we'd love help with. We're not voice experts, but some of you might be, let's make the distributable free software solution the best solution.
Fonte: link
O CMU Sphinx é um projeto de código aberto que também pode ser usado na área de trabalho, o Julius também.
No longo prazo, o Ubuntu Touch e o Ubuntu for Desktop serão o mesmo sistema operacional, então a resposta a perguntas como " pode ser usado também na área de trabalho? " deve ser cada vez mais positiva.