Below are the details on how people can translate without modifying the HTML or the files in the actual RSVP plugin.
Step 1 – Get a translation editor like Poedit. What this does is it allows you to quickly create a translation file based off of a POT file that is contained in the RSVP plugin.
Step 2 – Download the latest version of the RSVP plugin and unzip the file. Under the languages folder you should see a file called “rsvp-plugin.pot”. Like in the below screen shot.
Step 3 – Now that you know where that file is, go to Poedit and create a new translation and open the file rsvp-plugin.pot.
Step 4 – Once it is opened it will ask you to specify the language you can use the language code or name.
Step 5 – Now that the file has been created we should save it. Go to file -> save and then save it in the format of “rsvp-plugin-xx_YY.po” Where xx is the lower case version of your language code and YY is the upper case. For a list of language codes a good resource can be found at http://www.loc.gov/standards/iso639-2/php/code_list.php, you will want to use the ISO 639-1 Code.
Step 6 – Once that is saved the hard part starts, translating. Click on each row and enter in your translation text, like so:
Step 7 – Once you have entered in all of the text you can now include your two files one should end in .po and one should end in .mo. Into the languages folder of the rsvp-plugin install on your WordPress instance.