News Corp. launches MyNetworkTV (MNT) on Sept. 5, gambling on a concept never before tried on American television: offering low-cost, limited-run, hour-long nightly soaps based on Spanish-language telenovelas but performed in English. Programming has been a huge order for Twentieth Television, the Fox syndication division that has spearheaded MNT. It is producing six of the telenovelas at a large factory-like studio in San Diego, with two more concepts in development. Each telenovela will be spun out over 13 weeks. Twentieth has already completed production on its first two prime-time soaps, "Desire" and "Fashion House," and is shooting the next pair, "Art of Betrayal" and "Watch Over Me," slated to debut in December. Fox started MNT to create programming for nine News Corp.-owned UPN outlets that were suddenly orphaned; it debuts with 167 affiliates covering 96 percent of the nation.