The compatibility with ACF Pro is provided by Polylang Pro. This integration is available only for post types and taxonomies. It does not work yet for options pages (this is planned for a future version). There is however an integration contributed by the Be API Agency to achieve that, see: https://wordpress.org/plugins/acf-options-for-polylang/.
Before you start
Translating Fields Groups
Activate Fields Groups Translation
Translate a Fields Group
Translating fields values
Customize ACF fields behavior
Ignore
Copy once
Translate
Synchronize
With translated values
With copied values
The WPML configuration file
1. Before you start
The first question to ask yourself is: “Do I need to translate the label and the instructions?”
If yes, thus you need to translate your field groups in all your languages, you should read 2. Translating Fields Groups (see below). If not, it is preferable not to translate your field groups, you can skip to 3. Translating the fields values.
2. Translating Fields Groups
2.1 Activate the Field Groups translation
Go to Languages > Settings > Custom post types and Taxonomies and activate the translation as shown here:
2.2 Translate a Field Group
Go to Custom Fields > Field Groups.
As you see in the following screenshot, the field groups are now translatable. Before translating your field groups you need to activate the duplicate tool as below, it will allow you to copy all the content from the source field group to the translation.
We recommend you to create entirely your field group with the wanted custom fields before translating it. Indeed there is no synchronization between the translated field groups. It means that a modification made for example in the English field group won’t impact its French translation.
Once you have duplicated your field group into another language, you just need to edit new field group to translate the label and the instructions.
Important note: You must not modify the field name value across your translations. You must keep the same value.
3. Translating fields values
3.1 Customize ACF Pro fields behavior
Since Polylang Pro 2.7, you have the ability to fine tune how your ACF Pro fields will behave when you create new translations for your posts (and pages, and custom post types…). This happens directly in ACF Pro’s Custom Fields sub-menu (see picture below).
There are four options:
3.1.1 Ignore
When creating a new translation, each custom field for which you have selected the ‘ignore’ option will be left blank in the newly created translation.
3.1.2 Copy once
When translating a content (post, page, taxonomy …) in another language, Polylang decides which custom fields must be copied and which ones must be automatically ‘translated’. The custom fields that will be translated are:
image
file
gallery
post object
relationship
page link
taxonomy.
It means that Polylang prefills the field with the correct value when creating new translations. For example, if an ‘image’ custom fields is translated, Polylang will try to find the translation of the linked image, if it exists. This also works when these custom fields are included in repeater fields. If the translation doesn’t exist, Polylang will keep the value as is.
3.1.3 Translate
This is very similar to ‘copy once’, although these fields are expected to be translated after the translation has been created. We suggests that you choose this option for each custom field you intent on translating yourself, or through a translation service (whether manual or automatic).
This option is only available for the following fields:
Text
Text area
WYSIWYG editor
3.1.4 Synchronize
As a reminder, ‘synchronization’ means that a modification made in a content impacts all its translations. So after creation of a translation, and when the post (or page, or taxonomy, etc.) is modified the custom fields marked for ‘synchronize’ will then behave differently given of the kind of value you want to modify.
3.1.4.1 With translated values
If you decide to modify a translated value from a synchronized custom field, Polylang will automatically synchronize the custom field of all the other translations. In the example below we set the English value of a post object field to “A post in English”. As you can see in the following screenshot its translated French value “Un article en Français” is automatically copied to the translated French post.
3.1.4.2 With a copied value
If you modify a copied value (text, number, email, url custom field …) in a synchronized custom field, Polylang will automatically keep this same value in the translated English post.
A modification made on the layouts (group, repeater, flexible content) will impact the translations. For example, if you choose to add a flexible content in a French post, Polylang will automatically add this flexible content to the translated Englih post. It’s the same behavior if you decide to remove it.
Note: These options are not available for ‘Layout’ type of custom fields, but each sub-field can be customized on its own.
Important Note: Even if you have selected the custom fields synchronization option in Languages > Settings > Synchronization (see section Custom fields outside of ACF Pro ), the options you select for each ACF Pro custom field will override this synchronization.
4. The WPML configuration file
Alternatively, you can configure the way each custom fields behave when a content is translated by writing a wpml-config.xml file. Each custom field you add to this configuration file will override the behavior selected in the Custom Fields sub-menu. Also the wpml-config.xml applies to every custom fields from every plug-in, as well as those you added manually. See our documentation: The wpml-config.xml file