First of all, I followed this procedure. https://dev.sitecore.net/Downloads/Sitecore_Experience_Platform/101/~/link.aspx?_id=B685CC31771E466080080239FDBEA625&_z=z
I downloaded the necessary files from the following link "Client translations" and imported them. https://dev.sitecore.net/Downloads/Sitecore_Experience_Platform/102/Sitecore_Experience_Platform_102.aspx
At the end of procedure, I changed Display Language. Menu text has vanished.
At this time, we have also confirmed that the shell#lang of the cookie has been changed from en.
Both menus and cookies were restored by adding "sc_lang=en" to the end of the URL. However, the menu display language is still in English. What do I need to do to translate successfully?