diff --git a/mongoengine/queryset/base.py b/mongoengine/queryset/base.py
index 4a7452ce..b3cae684 100644
--- a/mongoengine/queryset/base.py
+++ b/mongoengine/queryset/base.py
@@ -206,7 +206,7 @@ class BaseQuerySet(object):
             raise OperationError(
                 "Is not possible to use search_text two times.")
 
-        query_kwargs = {'$search': text}
+        query_kwargs = SON({'$search': text})
         if language:
             query_kwargs['$language'] = language