Making chitchat before getting down to business the other day, Zambian President Kenneth Kaunda chided his latest African mission.

"I'm not usually so," the U.S. Ambassador to the United Nations allowed, "but I'm learning."

It is not really that Young has taken to heart the embarrassed rectifications that the State Department and even the White House felt obliged to make following some of this more controversial remarks in the early weeks after he took office. Rather, it's largely because the Carter administration has evolved an African policy of sorts - especially its determination to keep pressing Rhodesia and South Africa - that Young no longer looks so far out in front of the rest of the government.

his role in formulating that southern African policy may be debatedable, since the State Department, the President and Vice President and National Security Council all have contributed.

If his two-week tour of Africa proved anything, it is his ability almost single-handedly to communicate with black Africans what might be termed a suspension of disbelief about U.S. willingness to take positive action against the white-dominated governments of southern Africa.

"We're playing catchup," he has said in explaining African skepticism born of years of not-so-benign neglect. He has harped - occasionally to the irritation of blacks and whiter - on the lessons learned by the civil-rights movement in the American South.

In a less subtle tactician such insistence might be written off as a desire to recapture one's youth. But Young uses the Southern lesson, observers suspect, as a way of telling the American public that forceful measures against South Africa and Rhodesia need not be any more hurtful than was the case for white business in the American South.

Open to a point that shocks many African leaders more interested in rhetoric than results, Young is on record as saying "the American people are going to support a foreign policy they do not understand," especially after the trauma left by Vietnam.

"I try to make enough fuss so people [in America] will develop their own opinions about Africa," he added.

On another occasion he said, "I think the American people think the leaders of the [black African] liberation movements are a bunch of nuts, but most I met come on very reasonable."

But the fuss he wants to make is also in Africa, especially in South Africa where his visit on occasion appeared to have depressed him, if only because of the acceptance of apartheid he found among the best-intentioned whites and blacks.

Borrowing a favorite phrase from the late Martin Luther King, he described as the "paralysis of analysis" the impotent dithering of white South African university students more bent on emigrating than in bringing about change in the system.

Nothing Young said in South Africa or elsewhere appeared radical by either Young's civil-rights experience or by his earlier utterances as ambassador. Indeed, his constant celebration of the capitalist system would have merited loud cheers from many a boardroom. Perhaps fittingly his only direct confrontation with an adversary came from Marxist students at the University of Zambia at Lusaka, who attacked him relentlessly.

With established leaders, he had no such problems. He paid the Afrikaaners who run the South African government the honor of comparing President Carter to them. "I don't mind tough, hard-nosed people," he said, "They're a lot easier to deal with than idealists."

Such candor, of course, rests on the knowledge that for the Carter administration morality and national interest go hand in hand in southern Africa. The same cannot be said for Britain - whose investments amounts to $4.6 billion in South Africa alone, compared to $1.6 billion for the United States and $900 million for France.

Although he cajoled the radical African leaders - and often appeared to feel more comfortable in their presence than with the more pro-Western moderates - Young was not above telling them that their rhetoric in favor of armed struggle and/or Marxist economics has produced precious few positive results so far.

But since negotiations also have yet to prove their effectiveness in southern Africa, the radicals were quite content to have persuaded Young to come. For his presence forced that of the Security Coucil - Britain, France, West Germany and Canada - and scores of other countries that normally would have given the meeting the pass.

By persuading the major Western powers to bear witness at the conference, Young won the time necessary to press ahead with negotiations on Rhodesia and Namibia. He accomplished this to the annoyance even of some pro-Western Africans who do not share Young's views that "it just complicates things to talk of sanctions, embargoes and punishment."

All too aware that critics are still predicting Young cannot last long at the United Nations, Kaunda went out of his way to praise the Carter administration, yet say aloud what bothers many other Africans: "My worry is whether the American establishment will allow him to follow the line which is radical by U.S. standards."

What even so evenhanded a leader as Kaunda did not say is that Young's main problem is that of a man who believes in the enlightened values of self-improvement in an Africa whose leaders, black and white, rarely share such optimism or rationalism.