The National Endowment for the Humanities will request a 9 to 14 percent increase in federal funds for humanities projects and grants for fiscal year 1981, which begins in October 1980.

That budget proposal, due in two weeks, will call for between $109 million and $114 million from the federal government.

For fiscal year 1980 (which begins this October), the Endowment expects $100 million solely in program funds from the government. The total 1980 planned budget is $150.1 million, which includes other non-federal monetary gifts as well as money for administrative costs.

Endowment chairman Joseph Duffey refused to comment on the budget request at an open meeting yesterday of the National Council on the Humanities, an advisory body to the Endowment. But he did pass out a memo on the budget only to council members and asked that they not talk about specific numbers since there were press and public present.

"We've always been in an ambivalent position about this," Duffey said later. "We try to close as little of these meetings as possible. The general public has a right to know about budgets. But there has to be internal administrative discussion about the request."

Duffey did say to the council, "There is a tendency [in budgets in general] to inflate the language and promises, and that can hurt credibility. That's why it's important to use our language very carefully."

He will ask no increase in administrative funds for fiscal year 1981, sources said. Also, he is unwilling to use remaining current-fiscal-year funds for grant applicants who are not "highly recommended" by review panels, sources added. That may possible result in a surplus, which Duffey reportedly would return to the government.

On a lighter topic, there was much more energetic discussion. The council voted 12-9 to exclude foreign nationals from nomination for the prestigious Jefferson Lecture. This is a series of lectures given by a prestigious scholar. It carries a prize of $10,000.

"I assume we wouldn't invite de Tocqueville," grumbled council member Leon Stein when the proposal was brought up.

I can't think of a man who entertained broader possibilities of thought than Thomas Jefferson," said member Kaye Howe, a dissenter. "I'm sure he must be spinning in his grave at this discussion."

"But let's just clarify the situation for people like George Santayana or Alfred North Whitehead who spent time at Harvard and maybe bought a house but never got around to becoming an American citizen," said member Louis Hector.

"Well, I didn't know Jefferson well," countered member Robert Hollander, "but he was a practical man, and if we possibly can I think we should find an American. It's federal money."