How to write a handler for such a shortcode?

Question

WordPress

I have a WP Multilang multilingual plugin, it supplied such shortcodes [:en]Blooming Sky[:], [:de]500 ml[:en]500 ml[:] in products
that do not process I want to write a function myself that will leave only the name the desired locale, but the first time I met with this spelling [:en]Blooming Sky[:], [:de]500 ml[:en]500 ml[:]