One of England's most popular prime-time soaps is coming to the States, but not to California. "EastEnders," about a group of people living in London's Cockney-speaking East End, will be broadcast in January on public-television stations. For Americans accustomed to the mannerly "Masterpiece Theatre" and "Upstairs Downstairs," it may come as a shock. One character is an unwed mother with spiky punk hair, another is a homosexual. To cover the differences between American and English idioms, the BBC is considering marketing a special dictionary to be distributed by PBS. The plan involves assigning American employees to view 13 weeks of episodes, write down words that might be confusing and translate them into American slang. But officials at KCET Channel 28 say they won't be broadcasting the show. Greg Krizman, associate director of public information for the PBS station, said the show's not that different from American prime-time soaps and "we think our money can best be spent providing types of programming that isn't so readily available." He also objected to the program's 130 hours. "It would take a huge recommitment of scheduling time," he said.