adds new method

src/Umbraco.Examine/ExamineExtensions.cs

@@ -48,6 +48,31 @@ namespace Umbraco.Examine
             }
         }
 
+        /// <summary>
+        /// Returns all index fields that are culture specific (suffixed) or invariant
+        /// </summary>
+        /// <param name="index"></param>
+        /// <param name="culture"></param>
+        /// <returns></returns>
+        public static IEnumerable<string> GetCultureAndInvariantFields(this IUmbracoIndex index, string culture)
+        {
+            var allFields = index.GetFields();
+            // ReSharper disable once LoopCanBeConvertedToQuery
+            foreach (var field in allFields)
+            {
+                var match = CultureIsoCodeFieldNameMatchExpression.Match(field);
+                if (match.Success && match.Groups.Count == 3 && culture.InvariantEquals(match.Groups[2].Value))
+                {
+                    yield return field; //matches this culture field
+                }
+                else if (!match.Success)
+                {
+                    yield return field; //matches no culture field (invariant)
+                }
+                    
+            }
+        }
+
         internal static bool TryParseLuceneQuery(string query)
         {
             // TODO: I'd assume there would be a more strict way to parse the query but not that i can find yet, for now we'll

src/Umbraco.Web/PublishedContentQuery.cs

@@ -215,7 +215,7 @@ namespace Umbraco.Web
                 //search only the specified culture
 
                 //get all index fields suffixed with the culture name supplied
-                var cultureFields = umbIndex.GetCultureFields(culture).ToArray();
+                var cultureFields = umbIndex.GetCultureAndInvariantFields(culture).ToArray();
                 var qry = searcher.CreateQuery().Field(UmbracoContentIndex.VariesByCultureFieldName, "y"); //must vary by culture
                 qry = qry.And().ManagedQuery(term, cultureFields);
                 results = qry.Execute(count);