diff --git a/src/NadekoBot/Modules/Searches/Commands/GoogleTranslator.cs b/src/NadekoBot/Modules/Searches/Commands/GoogleTranslator.cs
index 5604fdd1..9cd0645c 100644
--- a/src/NadekoBot/Modules/Searches/Commands/GoogleTranslator.cs
+++ b/src/NadekoBot/Modules/Searches/Commands/GoogleTranslator.cs
@@ -1,4 +1,5 @@
-using Newtonsoft.Json.Linq;
+using System;
+using Newtonsoft.Json.Linq;
 using System.Collections.Generic;
 using System.Linq;
 using System.Net;
@@ -155,6 +156,11 @@ namespace NadekoBot.Modules.Searches
         {
             string text;
 
+            if(!_languageDictionary.ContainsKey(sourceLanguage) || 
+               !_languageDictionary.ContainsKey(targetLanguage))
+                throw new ArgumentException();
+            
+
             var url = string.Format("https://translate.googleapis.com/translate_a/single?client=gtx&sl={0}&tl={1}&dt=t&q={2}",
                                         ConvertToLanguageCode(sourceLanguage),
                                         ConvertToLanguageCode(targetLanguage),