The group trains so that everyone can pair with any other team member and use their powerful Unison attacks. But Shirabe is having trouble pairing up with anybody but Kirika, because of her inability to trust others.
I suppose this isn't something the 
younger generation is familiar with.
أعتقد أنّ هذا ليس شيئاً يألفه الجيل الأصغر
Die jungen Leute sind damit
wohl nicht mehr vertraut?
Los jóvenes no han de conocer
mucho de esto.
Los jóvenes no sabréis mucho de esto.
Immagino siano pratiche poco conosciute dai giovani.
Полагаю, молодёжь с этим не знакома.