For Example, if you want to change the following message:
"The task you tried to start is owned by some other user. Please Press the "Close" button to close this screen and return to the task list."
The above can also be done in a very simple format as follows:
Use the folder of the application what has already deployed. You will find several files named as Process Admin Messages_<lng>.properties in this folder. Backup the originals and edit the necessary files. Now save them and restart the server.
For changing the English messages, You have to use some Unicode converters.