In The Gambia, a common way to say "Welcome" is "Kenemaa!" (pronounced ken-eh-mah).
"Kenemaa" is Mandinka. In Wolof, you might hear "Nga def?" (How are you? / Welcome). English "Welcome" is universally understood in urban and tourist areas.
The Gambia (officially the Republic of The Gambia) is a small West African nation surrounded by Senegal, except for its 80 km Atlantic coastline. It's known for the Gambia River, rich birdlife, and vibrant culture.