Language customizer control

language-customizer-control.php

<?php 
        /**
         * Language
         *         
         */
        $wp_customize->add_setting( 'WPLANG', array(
                'type' 	      	        => 'option',
                'sanitize_callback'     => 'dbt_sanitize_language_choice',
        ) );
        $wp_customize->add_control( 'WPLANG', array(
                'section'       => 'dbt_settings',
		'type' 	        => 'select',
 		'label'         => __( 'Language' ),
		'choices' 	=> dbt_language_choices(),
                'priority'      => 70,
        ) );
        
        
        /** Language choices. */
function dbt_language_choices() {
        return apply_filters( 'dbt_language_choices', array(
                'de_DE'       	=> __( 'German' ),
                ''              => __( 'English (US)' ),
                'en_GB'         => __( 'English (UK)' ),
                'es_ES'       	=> __( 'Spanish' ),
        ) );
}

function dbt_sanitize_language_choice( $value ) {
        $choices = dbt_language_choices();

        if ( ! array_key_exists( $value, $choices ) ) {
                $value = '';
        }

        return $value;  
}