language field in database is other than i defined

[Saraylu]

I defined languages:

            'ml' => [
                'class' => MultilingualBehavior::className(),
                'languages' => [
                    'fa-ir' => 'Persian',
                    'en-US' => 'English',
                ],

but in database language stored as 'fa' and 'en'. I want languages to be saved as 'fa_ir' and 'en_us'.
How i do it?