Multi language has been added with the possibility of adding others, just copy the file and put it in the desired language. Example: lang-es.yml then add in config.yml under supported languages "es".
If you want to modify the old config.yml file do it as follows: Add: "InsufficientPoints: "&cInsufficient Points" and "Purchased: "&aYou have successfully purchased the item. &ePoints: {points}" to "Mess:"
and edit your "rewards:"
Below is the download of the config.yml file in case you need all the names!: