diff --git a/README.md b/README.md
index dd5113d..848a792 100644
--- a/README.md
+++ b/README.md
@@ -102,10 +102,11 @@ The action accepts the following parameters:
 | <nobr>`user_street`</nobr>             | String  | The street address of the contact                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                 |
 | <nobr>`user_postal_code`</nobr>        | String  | The postal code of the contact                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                 |
 | <nobr>`user_city`</nobr>               | String  | The city of the contact                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                 |
-| <nobr>`user_country`</nobr>            | String  | The country of the contact                                                          | [ISO 3166-1 Alpha-2 country codes](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2#Officially_assigned_code_elements)                                                                                                                                                                                                                                                                                                        |                                                                 |
+| <nobr>`user_country`</nobr>            | String  | The country of the contact                                                          | A [ISO 3166-1 Alpha-2 country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2#Officially_assigned_code_elements)                                                                                                                                                                                                                                                                                                       |                                                                 |
 | <nobr>`user_telephone`</nobr>          | String  | The telephone number of the contact                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                 |
 | <nobr>`user_company`</nobr>            | String  | The company of the contact                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                 |
 | <nobr>`user_extrafield`</nobr>         | String  | Additional information of the contact                                               |                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                 |
+| <nobr>`user_language`</nobr>           | String  | The preferred language of the contact.                                              | A [ISO-639-1 2-digit language code](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes)                                                                                                                                                                                                                                                                                                                                    |                                                                 |
 | <nobr>`campaign_id`</nobr>             | Integer | The CiviCRM ID of a campaign to assign the contribution                             | A valid CiviCRM Campaign ID. This overrides the campaign ID configured within the profile.                                                                                                                                                                                                                                                                                                                                    |                                                                 |
 
 You may also refer to
diff --git a/api/v3/TwingleDonation/Submit.php b/api/v3/TwingleDonation/Submit.php
index de8fee4..9a64f3e 100644
--- a/api/v3/TwingleDonation/Submit.php
+++ b/api/v3/TwingleDonation/Submit.php
@@ -224,7 +224,7 @@ function _civicrm_api3_twingle_donation_Submit_spec(&$params) {
     'api.required' => 0,
     'description'  => E::ts('The company of the contact.'),
   );
-  $params['user_extrafield'] = array(
+  $params['user_language'] = array(
     'name'         => 'user_language',
     'title'        => E::ts('Language'),
     'type'         => CRM_Utils_Type::T_STRING,