Example. A code used to translate labels in the Ultimate Member member directory. Uses the Polylang or WPML language switcher.

um_translate_labels.php

<?php

/**
 * Translate labels with Polylang or WPML.
 */
function um_get_translated_labels() {
	// EDIT this array of translated labels.
	return array(
		"first_name" => array(
			'en' => 'First Name',
			'es' => 'Nombre de pila',
			'fr' => 'Prénom',
		),
		"last_name" => array(
			'en' => 'Last Name',
			'es' => 'Apellido',
			'fr' => 'Nom de famille',
		),
		"role_select" => array(
			'en' => 'Account Type',
			'es' => 'Tipo de cuenta',
			'fr' => 'Type de compte',
		),
	);
}

function um_translate_field_label( $label, $key ) {
	if ( defined( 'ICL_SITEPRESS_VERSION' ) ) {
		$lang = apply_filters( 'wpml_current_language', null );
	} elseif( function_exists( 'pll_current_language' ) ) {
		$lang = pll_current_language();
	} else {
		$lang = substr( get_locale(), 0, 2 );
	}
	$labels = um_get_translated_labels();
	if ( array_key_exists( $key, $labels ) && array_key_exists( $lang, $labels[ $key ] ) ) {
		$label = $labels[ $key ][ $lang ];
	}
	return $label;
}

function um_translate_filter_label( $attrs, $key ) {
	$attrs['label'] = um_translate_field_label( $attrs['label'], $key );
	return $attrs;
}

add_filter( 'um_change_field_label', 'um_translate_field_label', 10, 2 );
add_filter( 'um_search_fields', 'um_translate_filter_label', 10, 2 );

There is no easy way to translate labels in the member directory. You can use the um_change_field_label hook to translate field labels and the um_search_fields hook to translate filter labels. See code example above.

Extend an array in the um_get_translated_labels function to add more fields and languages.

This code works with the Polylang or WPML multilingual plugin. You have to use another function to get the $lang variable (current language) if you use another multilingual plugin.

Directory example