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

assets/romfs/i18n/it.json

@@ -30,6 +30,9 @@
   "Sd": "SD",
   "Image System memory": "Immagine memoria di sistema",
   "Image microSD card": "Immagine scheda microSD",
+  "Slow": "",
+  "Normal": "",
+  "Fast": "",
   "Yes": "Sì",
   "No": "No",
   "Enabled": "Abilitato",
@@ -87,6 +90,7 @@
   "Portuguese": "Português",
   "Russian": "Русский",
   "Swedish": "Svenska",
+  "Vietnamese": "Vietnamese",
   "Logging": "Logging",
   "Replace hbmenu on exit": "Sostituisci hbmenu all'uscita",
   "Misc": "Varie",
@@ -95,6 +99,7 @@
   "Install forwarders": "Installa forwarder",
   "Install location": "Installa posizione",
   "Show install warning": "Mostra avvertimento installazione",
+  "Text scroll speed": "",
 
   "FileBrowser": "FileBrowser",
   "%zd files": "%zd files",
@@ -233,6 +238,7 @@
   "Update avaliable: ": "",
   "Download update: ": "",
   "Updated to ": "",
+  "Press OK to restart Sphaira": "",
   "Restart Sphaira?": "",
   "Failed to download update": "",
   "Restore hbmenu?": "",
@@ -246,4 +252,4 @@
   "Are you sure you want to delete ": "Sei sicuro di voler eliminare? ",
   "Are you sure you wish to cancel?": "",
   "If this message appears repeatedly, please open an issue.": ""
-}
+}