More than 50 years after the musical “West Side Story” had its original Broadway premiere, it is set to return in February in a darker, grittier, bilingual revival, the show’s producers said on Wednesday. In an element that its director, Arthur Laurents, said would heighten the passion and authenticity of the show, much of the dialogue — both spoken and sung — will be in Spanish. “They will speak Spanish where they would naturally,” Mr. Laurents said in a telephone interview from his home in Quogue, N.Y., adding that supertitles would be used to aid the audience. “The scenes with...