The impact of immigration on the state economy is becoming more significant as the number of workers born in another country has doubled in the past 25 years, according to a study released last month by a Boston-based think tank. The report by MassINC, titled "The Changing Face of Massachusetts," explained that a new immigrant population lacks English proficiency necessary for an increasingly competitive labor force. "Businesses say, of course, they want a skilled workforce," said Jane C. Edmonds, director of the Massachusetts Department of Workforce Development, who was one of six panelists discussing the implications of the MassINC study...