add new strings and update ko.json, ja.json (#88)

assets/romfs/i18n/zh.json

@@ -30,6 +30,9 @@
   "Sd": "SD卡",
   "Image System memory": "主机内存图像",
   "Image microSD card": "SD卡图像",
+  "Slow": "",
+  "Normal": "",
+  "Fast": "",
   "Yes": "是",
   "No": "否",
   "Enabled": "启用",
@@ -87,6 +90,7 @@
   "Portuguese": "Português",
   "Russian": "Русский",
   "Swedish": "Svenska",
+  "Vietnamese": "Vietnamese",
   "Logging": "日志",
   "Replace hbmenu on exit": "退出后用Sphaira替换hbmenu",
   "Misc": "拓展",
@@ -95,6 +99,7 @@
   "Install forwarders": "允许安装前端应用",
   "Install location": "安装位置",
   "Show install warning": "显示安装警告",
+  "Text scroll speed": "",
 
   "FileBrowser": "文件浏览",
   "%zd files": "%zd 个文件",
@@ -233,6 +238,7 @@
   "Update avaliable: ": "有可用更新！",
   "Download update: ": "下载更新：",
   "Updated to ": "更新至 ",
+  "Press OK to restart Sphaira": "",
   "Restart Sphaira?": "重启 Sphaira？",
   "Failed to download update": "更新下载失败",
   "Restore hbmenu?": "恢复 hbmenu？",