During the brief hearing that preceded the Senate's recent confirmation of Langhorne A. (Tony) Motley as assistant secretary of State for inter-American affairs, Sen. Jesse Helms (R-N.C.) asked Motley whom he plans to use as his deputies in guiding President Reagan's controversial Latin America policies.

Motley replied noncomittally that he hadn't focused on personnel matters yet. But underlying the brief exchange is a problem that played a big part in the departure of Motley's predecessor, Thomas O. Enders, and could cause some headaches for the new assistant secretary.

The problem involves the determination of Helms and other conservatives that their hard-line views on combating communism in this hemisphere be represented within the Bureau of Inter-American Affairs.

That meant a two-year tug-of-war in which Enders was forced to fight a series of rear-guard actions against conservative efforts to get him to accept as deputies people who were regarded within the State Department as unqualified or extremist.

One conservative-backed candidate, Gordon Sumner, a retired Army general, was shunted into a consultant's job; another Helms nominee, Lewis Tambs, a history professor with strongly conservative views, was offered the ambassadorship to Panama and, after the Panamanians objected, was made ambassador to Colombia.

But the persistence of Helms and his allies continually frustrated Enders' efforts to get what he regarded as qualified help. In contrast to other assistant secretaries who have four or five deputies, Enders never had more than two.

Earlier this year, when his two chief aides were promoted to other jobs, the replacements he chose from within the Foreign Service were vetoed by the White House in response to conservative pressure.

Helms, chairman of the Senate Foreign Relations subcommittee on Western Hemisphere affairs, continued to push for the appointment of various academicians or foundation scholars known for their conservative views.

Enders is known to have complained in private that those proposed by Helms do not command much respect among Latin American scholars or they espouse ideas that are mistrusted by the governments of the region.

As a result of the standoff, Enders was running Latin American policy with only one deputy and a number of temporary "special assistants" when he was dropped as assistant secretary.

Now, as Motley prepares to put his team in place, he is on notice that Helms will be looking over his shoulder with a list of people he would like to see in the key jobs. AMBASSADORIAL MUSICAL CHAIRS . . . Motley's appointment means that the department will have to find a new ambassador to Brazil, where Motley served for two years. While Reagan has given no indication of whom he plans to send to the largest country in Latin America, the rumor mill already is churning out names.

One theory is that Deane R. Hinton, recently replaced as ambassador to El Salvador, will be reassigned to Argentina, and that the present U.S. envoy in Buenos Aires, Harry W. Shlaudeman, will move to Brasilia. However, other department sources say that they believe Hinton plans to retire.

Still others contend that if Reagan opts to send a career diplomat to Brazil, a strong possibility is William H. Leurs, a former ambassador to Venezuela now returning to duty after an academic leave at Princeton. FOREIGN ACCENTS . . . Remember Steven Seymour, who had a brief moment of unenviable fame in 1977 when he acted as President Carter's interpreter in Warsaw and somehow managed to turn Carter's arrival statement that he wanted "to understand your desires for the future " into "I desire the Poles carnally."

Among those who do remember are Rep. Leon E. Panetta (D-Calif.) and Rep. Paul Simon (D-Ill.). They have introduced legislation "to improve the translation and interpretation services available to the U.S. government" by creating a Bureau of Language Services in State to be headed by an assistant secretary.

The department officially has no position on the proposal, but officials privately say that it's not needed or wanted. They insist that the department's simultaneous interpretation needs are adequately served by its present full-time staff of 20 interpreters who collectively can work in Russian, Spanish, German, Italian, Portuguese, French, Arabic, Chinese and Japanese.

When there's a need for interpretation in other languages, the department can call on more than 100 part-time specialists. Seymour was one of those.

Despite his performance in Warsaw, other people in the field say that he really is an excellent interpreter who just got rattled and had a bad day.