IN AN APTLY FOCUSED gesture of concern, Averell Harriman is about to make a very large improvement in the endowment of Columbia University's Russian Institute. Like others who know something about the subject, Gov. Harriman -- who was ambassador to Moscow during World War II -- is dismayed by the state of neglect into which Soviet studies have fallen in this country over the past two decades. Numbers of students and amounts of money have both fallen sharply. It is precisely for these reasons that the Senate is now considering the Soviet-bloc research and training act, a bill designed to support, with a federal endowment, the same larger purposes that Gov. Harriman has in mind.

The Harriman gift and the proposed federal fund could hardly be more valuable to the country. But they raise another disquieting question: if there's been neglect at the highest levels of the academic world, what about the preparation available to interested youngsters earlier in their education? A command of the Russian language is the essential tool in this field. In the American educational system, when does the future Soviet specialist start learning the language?

There are 82 high schools in Washington and its immediate suburbs. You can, literally, count on the fingers of one hand those that offer Russian: Robinson Secondary near Fairfax, South Lakes in Reston, T. C. Williams in Alexandria, Bethesda-Chevy Chase, and Wilson in Washington.

In the early 1970s, Fairfax County routinely offered Russian in all of its high schools. The reason for discontinuing it has little to do with budget cuts. As one official explains, it was simply a lack of interest among the students -- and that explanation is echoed throughout the area. Does that not strike you as extraordinary? If competence in Russian is regarded as dispensable in this city of diplomats, military officers, journalists and travelers, where would you expect it to be adequately supported?

Russian instruction survives in even those five high schools, you can safely assume, only because energetic and gifted teachers actively recruit students and, in the face of general public indifference, persuade them that competence in languages is necessary.

The new plans for funding graduate studies in Soviet affairs can make an important difference. But the level at which graduate students work will always be influenced by the preparation, or lack of it, available to them many years earlier.