# if you want to enqueue your style in you theme, rtl or else

function theme_enqueue_scripts() {

    # enqueue style in your theme

    wp_register_style( \'rtl\', get_template_directory_uri() . \'/css/rtl.css\', array(), \'1.0.0\' );
    wp_enqueue_style( \'rtl\' );


}
add_action( \'wp_enqueue_scripts\', \'theme_enqueue_scripts\' );

# if you need enqueue this, just if theme is rtl , copy this function

function theme_enqueue_scripts() {

    if ( is_rtl() ) {

        wp_register_style( \'rtl\', get_template_directory_uri() . \'/css/rtl.css\', array(), \'1.0.0\' );
        wp_enqueue_style( \'rtl\' );

    }


}
add_action( \'wp_enqueue_scripts\', \'theme_enqueue_scripts\' );

更改语言时，WordPress会自动加载rtl。css。这是怎么发生的explained here.

至于使用rtl。css没有切换到rtl语言，你读过Codex page? 有一些自动化工具可以帮助您翻转网站。