Perfex CRM - Language files for Surveys module. Version 2.3.0
Read more about languages
If you need to overwrite translation texts you can create your own file and replace existing translation with your own, in this case you wont need to worry when upgrading the software.
Follow this article: https://help.perfexcrm.com/overwrite-translation-text/
Language files in Perfex CRM use the UTF-8 encoding without a Byte Order Marker, when creating language override files it is important to maintain the same encoding.