Multilingual title and description in WordPress with bogo

function.php

add_filter( 'option_blogname', 'tr_option_blogname' );

function tr_option_blogname( $blogname ) {
    return __($blogname, 'my-theme-child');
}

add_filter( 'option_blogdescription', 'tr_option_blogdescription' );

function tr_option_blogdescription( $blogdescription ) {
    return __($blogdescription, 'my-theme-child');
}

add_action( 'after_setup_theme', 'my_child_theme_setup' );
function my_child_theme_setup(){
    load_child_theme_textdomain( 'my-theme-child', get_stylesheet_directory() . '/languages' );
}

ja.po

#: Site Title
msgid "English Title"
msgstr "日本語のタイトル"

#: Site Description
msgid "Description in English"
msgstr "日本語のキャッチフレーズ"

style.css

/*
 Theme Name:  My Theme Child
 Description: My Theme Child Theme
 Author:      Jonh Doe
 Author URI:  http://www.example.com
 Template:    my-theme
 Version:     1.0.0
 Tags:        
 Text Domain: my-theme-child
*/