Literal translation
water makes [one] become pretty
Meaning
water makes you beautiful
Explanation
Aigo means water, veni means to come or to become, and poulit means nice, pretty, or polite; l'aigo fai veni poulit thus literally translates as water makes [one] become pretty, or makes one become polite, given the double sense of poulit covering both pleasant appearance and polite manners. In use, the expression simply asserts that water makes you beautiful, praising the virtues of cleanliness and regular washing for one's looks, a piece of popular common sense presented as a general truth. The double meaning of poulit also allows the phrase to be read as a broader encouragement toward cleanliness, said to make one not only pretty but also well-mannered, the two qualities being traditionally linked in the popular upbringing of children. The register is proverbial and instructive, close to the advice given to a reluctant child at bath time, in an oral tradition where water is valued both as a scarce resource, as the neighboring saying about water and gold recalls, and as an agent of beauty and good manners.