This plugin, which requires polylang
provides the means to include posts that have no translation in the current
language on pages of posts.
Usage
Multilingual Polylang provides two public functions:
The function MultilingualPolylang::get_query() returns a WP_Query object with posts from
all languages but where there is a translated post, only the post in the current
language will be included
The function MultilingualPolylang::get_permalink() can be used as a drop-in replacement to
    get_permalink(). This will replace the language in a post URL so that a post
can be viewed in a language different to that of the rest of the interface.
Development
This plugin uses wp-cli and PHPUnit for testing.
Download the source code from GitHub
$ git clone git@github.com:aptivate/multilingual-polylang.git
Install wp-cli
If not already present, install wp-cli
Install PHPUnit
If not already present, install PHPUnit
Install the test WordPress environment
$ cd multilingual-polylang
$ bash bin/install-wp-tests.sh test_db_name db_user 'db_password' db_host version
where:
-  
test_db_nameis the name of your temporary test WordPress database -  
db_useris the database user name -  
db_passwordis the password -  
db_hostis the database host (eglocalhost) -  
versionis the version of WordPress (eg4.7.5orlatest) 
Run the tests
From the plugin directory:
$ phpunit