Ryuhei Yokokawa

Plugin will allow you to fetch the WP-API (WP-JSON-API) call with a “lang” variable. It will retrieve the right content from WPML/WP.
This only works with WPML and WP-API installed. I tested only with the latest version as of now: 
* WPML 3.1.9.6 
* WP REST API 1.2.1

WPML to WP API

Allows you to request a language with your WP-API and WPML site.

aiyaz Khorajia

JSON API DELETE USER extends the JSON API Plugin with a new Controller to delete user with meta data.
<h3>Documentation</h3>
<ul>
<li>
You need to create nonce to delete user, nonce can be created by calling http://localhost/api/get_nonce/?controller=user&method=delete_user_with_meta
</li>
<li>
You can then use ‘nonce’ value to delete user.
</li>
</ul>
= Method: delete_user_with_meta=
You can find example.php file to understand delete user api call via curl.
http://localhost/wordpress/api/user/delete_user_with_meta?email=example@domain.com

JSON API Delete User

Delete User with meta details add-ons for JSON API

WPML to WP API vs JSON API Delete User