Clarify that english is the default; add reference for more info (#6081) (#6125)

* Clarify that english is the default; add refernce for more info

* update references

* links can not start with $

* how many times can I mess up a ref?

Author: MongoCaleb

source/core/indexes/index-types/index-text/specify-language-text-index/create-text-index-multiple-languages.txt

@@ -93,7 +93,15 @@ The following operation creates a text index on the ``original`` and
 
 .. code-block:: javascript
 
-   db.quotes.createIndex( { original: "text", "translation.quote": "text" } )
+   db.quotes.createIndex({ original: "text", "translation.quote": "text", "default_language" : "fr" })
+
+.. note::
+
+   English is the default language for indexes. If you do not specify the 
+   :ref:`default_language <createIndexes-default-language>`, your query must 
+   specify the language with the :ref:`$language <language-field>` parameter. 
+   For more information, refer to :ref:`<specify-default-text-index-language>`.
+
 
 Results
 -------

source/reference/command/createIndexes.txt

@@ -300,13 +300,14 @@ Each document in the ``indexes`` array can take the following fields:
        :ref:`control-text-search-results` to adjust the scores.
        The default value is ``1``.
 
-       
- 
+
    * - ``default_language``
 
      - string
 
-     - Optional. For :ref:`text <index-type-text>` indexes, the language that
+     - .. _createIndexes-default-language:
+
+       Optional. For :ref:`text <index-type-text>` indexes, the language that
        determines the list of stop words and the rules for the stemmer and
        tokenizer. See :ref:`text-search-languages` for the available
        languages and 

source/reference/operator/query/text.txt

@@ -75,7 +75,10 @@ following fields:
 
    * - ``$language``
      - string
-     - Optional. The language that determines the list of stop words for the search and
+
+     - .. _language-field:
+
+       Optional. The language that determines the list of stop words for the search and
        the rules for the stemmer and tokenizer. If not specified, the search
        uses the default language of the index. For supported languages, see
        :ref:`text-search-languages`.