Translation review is an optional stage in the translation process in which an experienced translator can check that translations are of sufficient quality.
Without translation review, translators will save translations in the 'translated' state, making them immediately available to download and use for your project.
If it's turn on, translations in the 'translated' state are not considered ready for download. Instead, a reviewer must look at the translations and change them to 'approved' or 'rejected' state. Only translations in 'approved' state are considered ready for download.
Translation review adds extra time and effort to the translation process, so is not recommended for all projects. Translation review can be activated at a later time if it becomes necessary.
Turning review off and on will not cause approved translations to lose their approved status. Approved translations will remain approved unless they are replaced with another translation. When review is turned off, approved translations will be treated the same as translations in the 'translated' state.