Can American teen-agers ease the strains in the Atlantic alliance? Twenty million dollars say, ''Yes.'' That's the amount of money President Reagan has called for in his President's International Youth Exchange Initiative (PIYEI) - a public/private partnership designed to increase the number of exchanges of 15- to 19-year-olds between the United States and the other six nations that met at the Versailles summit in June of 1982.
And if the local PIYEI coordinating group in Boston has its way, some of that money will be steered toward inner-city students - a group that traditional youth-exchange programs have left almost untapped.
When he kicked off the program last May, the President noted that ''one of the best ways to develop more accurate perspectives on other nations and on ourselves is for more Americans to join, for a time, a family and a community in another land.''
The initiative, now headed by Charles Z. Wick, director of the United States Information Agency (USIA), caught many youth-exchange officials by surprise. Coming from a President not noted for international concerns - and whose conservative constituency seems to some observers to be oriented more toward protectionism than overseas interests - it was greeted with some skepticism.
But the Versailles summit partners joined in the initiative, and last October the US Senate passed a resolution supporting it. Now, after months of planning, it is moving ahead on three fronts:
Local. Committees in 19 ''pilot project'' communities around the country, from Charlotte, N.C., to Salem, Ore., are researching ways to promote international exchanges within their communities. The local committees work through such established programs as AFS, Youth for Understanding, and the Experiment in International Living - tying the project closely to international support groups already in place in the communities. The pilot projects were established through grants from the USIA and the Kettering Foundation.
National. A national Council for International Youth Exchange has been formed to coordinate private-sector fund raising. Composed of some 100 top US leaders in business, industry, and education, it met in January and established the goal of raising $10 million. It already has some $2.4 million on hand: $1 million in private funds originally contributed to but never needed for President Reagan's 1981 inaugural, and $1.4 million from corporate and foundation donors. The money will be used to double (from 5,000 to 10,000 a year) the numbers of US exchange students travelling abroad over the next three years.
International. Representatives from the summit countries - Canada, France, Germany, Italy, Japan, Britain, and the US - held a three-day meeting in Williamsburg, Va., late last month to plan the exchanges. ''Every country has the complete freedom to define its collection of activities which it wants to call youth activities,'' says USIA official Molly Raymond. She says the meeting produced ''a real sense of commitment'' from the member nations.
There are still some rough patches to be ironed out, however. One close observer, full of praise for the community-level approach, expressed concern that the USIA was turning the project into a ''top down'' effort orchestrated from Washington.
Some youth-exchange organizations initially felt excluded from the planning process. The plans named a consortium of eight groups as potential recipients for the money - and left out others, such as the YMCA. But Alice Mairs, the YMCA's director of international program services, says she's now been assured consortium members will not be the only ones to receive funding.
Some exchange officials also worry that the program is too narrowly conceived. Ms. Mairs notes that German officials, with whom she met in December, hope to expand their exchanges beyond the teen-age, home-hosted, full-term academic programs encouraged by the PIYEI. They would like to include nonstudent farm youth, for example, or sports teams. AFS official Susan Steel says her program, in order to remain nonideologi-cal and apolitical, must spread its funding across all 60 countries it serves. Any proposal it makes for PIYEI funding, she says, will be designed to ''expand international exchanges with all our countries'' - and not just those in the Western alliance.
But Mr. Wick says he is ''very satisfied'' with the progress - adding that ''in taking soundings, we are encouraged that we are on a sturdy, sound course.''
At this point, much of the planning remains in flux. The local community group in Boston, for example, is apparently unique among the 19 in focusing on inner-city exchanges.
The problems, say those close to the process, are formidable. Inner-city students sometimes lack adequate preparation in a second language. City schools often have no traditions of accepting foreign students, and the communities frequently lack suitable host homes. ''It is too often considered by many of our students a broadening cultural experience to go from one neighborhood to another ,'' says Boston School Committee president Kevin McCluskey.
But exchanges do occur. Kitty Flynn, a mother in the inner-city Boston neighborhood of Dorchester, has hosted students from Colombia, Finland, Norway, Belgium, and Germany through Youth for Understanding. ''This exchange business really does work,'' she says.