Why can't I make the messaging widget title multilingual?

hi.
I am using the Messaging Widget.
I have zE('messenger:set', 'locale', "{{ App::getLocale() === 'ja' ? 'ja' : 'en-US' }}"); to achieve multilingual support.
However, there is a problem: this program does not apply to the title of the attached image. Why are the titles not translated? And is there any way to translate them?