Providence Talks, an early-childhood program aimed at closing the word gap, is expanding into five additional U.S. cities. Bloomberg Philanthropies announced Tuesday that Birmingham, Alabama; Detroit; Hartford; Louisville and Virginia Beach are picking up the program. The growth comes against the backdrop of a Brown University study that concluded the intervention — designed to increase the number of words heard by children in lower-talk households — does work, but that some parts of it are more effective than others, leading Providence Talks to tweak the way it offers the services. The program plans to offer more “play groups” for 10 weeks. The families, which meet once a week, spend time reading to their children, reviewing the pedometer word counts with staff and getting coached. “We trying to focus on habits that lead to school readiness,” a program staffer said.