Please contact our developer team and request the localization. We will review your request and, if approved, we will send you Excel files with strings to translate. Once we receive the files with translation from you, we will try integrating the new translation into the next release.
However, you should realise that the initial translation is just part of the localisation work. The most time consuming task is to support the localization for the new versions. The localization files need to be updated/expanded every time we add or change features in Survey Solutions.