How can I create custom plugins?

[wyvern800]

I am needing to create custom option on the commands menu, which will be:
Add template variables, something like a button that I click and it add {{params.title}} string to the editor, which will act like an email template variable. is that done by interacting directly with the Editor API or would that be possible trough the plugin system? I even tried to duplicate a paragraph extended with custom HTMLAttributes but then the editor recognizes only the plugin near to the end of the array, and ignores the ones that comes before.

Also is it possible to translate all the menus to Portuguese?