The Prince George's County Educators Association, representing more than 6,000 county teachers, asked the school board for a 5 percent salary increase in contract talks that began yesterday for the school year 1983-84.

The salary request, which would cost about $7.5 million, is 1.1 percent above the 3.9 percent rise in the Consumer Price Index over the last 12 months.

Union president John C. Sisson called this year's talks, "a radical departure from the past," because the union has forgone the traditional bargaining stance of starting high and settling in the middle.

In November 1980, as negotiations began for the current two-year teachers' contract which ends in June, the union enraged school officials by demanding a 43 percent increase for the first year. The eventual settlement -- at 9.1 percent for the first year and just over 6 percent this year -- left some divisions within the union leadership.

Sisson said this year's 5 percent request was "reasonable and defensible," particularly since county teachers are the lowest paid in the metropolitan area. The median teacher in Prince George's, with 14 years' experience and a master's degree, currently makes $27,876. The same teacher makes $28,340 in Fairfax County, $28,650 in Montgomery and $28,469 in Arlington.

Baltimore County teachers recently settled for a 5.5 percent increase, while Montgomery teachers are to get 5 percent under their present contract, according to Chet Elder, chief negotiator for the Prince George's teachers.

School Superintendent Edward J. Feeney has said that the teachers deserve a "reasonable" settlement, but school spokesman Brian J. Porter noted that, "there are several unanswered questions -- including the potential underfunding of the board of education budget next year."

The union also is making two novel proposals aimed at stemming the impact of possible layoffs if, like last spring, the County Council cuts Feeney's budget request for lack of funds. The first would allow teachers to voluntarily work half-time without losing seniority in order to create new teaching positions.

The second proposal would give cash bonuses to teachers who choose early retirement after 25 years of service. Under the state retirement system, those teachers currently are penalized up to 30 percent of their retirement pay for leaving the system early.

Feeney has submitted a $317.5 million budget to the county school board, but it does not include the requested cost-of-living increase for teachers. That item, of $7.5 million, would bring the overall school budget to $325 million.