The literal translation for this proverb could be: “Salt does not boast of being salty.”
Some people were born with a particular aptitude, and some others have developed it. And the confidence in their capacity/ability gives them some pride.
When people seem not to see their skills/job/accomplishment they say that loudly. Some people might go as far as calling people to tell them how good they are doing something or being someone in particular.
Haitians say this proverb to teach humility. We do not have to tell everyone what we have accomplished or how good we are as a professional/parent/teacher/…. Our skills should be meant to serve others but not to take us out of the crowd even if the results do.
We should recognize the talent and accomplishment of somebody.
But any time we see someone boasting about them remind him/her that: “Sèl pa janm vante tèt li di l sale”.
Proverbs 27:2 tells us: “Let someone else praise you, not your own mouth— a stranger, not your own lips.”
