From: Wolof, West Africa
Source: Wolof (Senegal) oral-tradition proverb; no. 1 in African Manners, "Wolof Proverbs: 146 in Total" (africanmanners.wordpress.com), as "He who knows swimming, dies not in the water", with the Wolof in an old transcription: "Kou mana faiya dou jarou thy ndoje". Earlier recorded here as from Richard Shawyer, "Wisdom of the Wolof Sages" (2009); that book has not been checked.
The meaning given here is our own reading. Other interpretations exist.