[init] handle the case in which translate() gets called with no dictionary.

init.lua

@@ -90,8 +90,9 @@ end
 --
 -- @return localized and formatted string.
 function moonspeak.translate(id, ...)
-    local msg = rawget(moonspeak.dict, id)
+    local dict = moonspeak.dict
     local lang = moonspeak.lang
+    local msg  = dict and dict[id] or nil
 
     if msg ~= nil and msg[lang] then
         -- Found localized string.