$ sudo apt-get update
$ sudo apt-get install python-pocketsphinx 

python-pocketsphinx is installed in your system.

Make ensure the python-pocketsphinx package were installed using the commands given below,

$ sudo dpkg-query -l | grep python-pocketsphinx *

You will get with python-pocketsphinx package name, version, architecture and description in a table

python-pocketsphinx package basic information: