If you are wanting to translate Simple Review into another language or simply to change some of the default text you can find the language files here:
There is a directory for each language and inside each directory are files containing text.
By default Simple Review comes with English (en-GB) and German (de-DE), if you want to provide a translation e.g. simplified Chinese (zh-CN) copy the en-GB directory and rename it (e.g. zh-CN) and then edit the files.
The files are grouped into logical modules e.g. comment related text lives in Comment_Module.php. The language files contain a list of key-value pairs
key => value, you only need to change the value part.
For example, if you wanted to change the text that is displayed after the user has added a comment you would open the file www/administrator/components/com_simple_review/addons/modules/Locale_Module/languages/en-GB/Comment_Module and change this line:
'Added' => 'Your comment has been added.',
'Added' => 'Your AMAZING comment has been added.',
It is very important than you only modify the part between the single quotes (if you want to use a single quote you must escape it by adding a backslash in front of it i.e. \’). You must also make sure that your text editor (I would recommend notepad++) saves the file using the correct encoding, in most cases you should use Unicode (UTF-8, no BOM). I would also recommend only translating one file at a time so that it is easier to test for any problems.

If you have made a translation or have any problems please post on the forum.