Forms on multilingual sites (WPML)

Forms use CAFE's WPML integration like edit screens do.

Labels and instructions are shown in the current language (the same cafe_field_label / cafe_field_instructions translations as edit screens).
Edit forms on a translation: fields set to Copy show the original's value read-only and are never saved from the form; Translate fields save on the translation; Copy once fields are editable.
Create forms: WPML gives the new post a language when it is saved, normally the language of the request. AJAX submits go through the REST API; check on your site that new posts get the language you expect, and set it in cafe_dynamic_form_saved with WPML's wpml_set_element_language_details action if not.
Form texts you pass as arguments (submit_label, success_message) are plain strings. Translate them in PHP:

cafe_dynamic_form( [
	'id'              => 'new-event',
	'field_groups'    => [ 'group_event_details' ],
	'submit_label'    => __( 'Send event', 'my-theme' ),
	'success_message' => __( 'Thanks! We will review your event.', 'my-theme' ),
] );

Forms made in CAFE → Forms keep their texts in one language; use cafe_dynamic_form_args to translate them:

add_filter( 'cafe_dynamic_form_args', function ( array $args ) {
	if ( 'event-sign-up' === ( $args['id'] ?? '' ) ) {
		$args['submit_label'] = __( 'Send event', 'my-theme' );
	}
	return $args;
} );

Redirects: use a translated address, e.g. with apply_filters( 'wpml_permalink', $url ) in cafe_dynamic_form_redirect.