Philadelphia, a city known for ’70s soul and other classic sounds, is now welcoming a groove from where crawfish got soul—zydeco.

In June, Philadelphia public-radio station WXPN announced “Zydeco Crossroads”—a 15-month project presenting south Louisiana’s accordion dance music through a series of concerts, educational events and a new documentary film by producer Robert Mugge, whose works include the post-Katrina film