“(unknown current hero — generic language-app pattern)”
The hero does not declare who Mango is for or why it exists. A visitor scanning language-app options sees no reason to investigate further. The library-access angle — the single most differentiating fact — requires navigation to a separate page.
“Learn 70+ languages free through your library. Already have a card? Start now.”
Leads with the offer (free), the mechanism (library card), and the breadth (70+ languages). The question format ("Already have a card?") creates an immediate personal relevance check that drives clicks.