May 19, 1985

ATRANSLATOR has been commissioned at 5 cents a word to render a 500-page Czech novel into English. He has three months to perform his task. The author is hot - the winner of a prestigious literary prize or a recently jailed dissident. Right on page 1, our speedy translator comes across the following line: ''Sam vsechno vyzvonil, a ted jsme v rejzi.'' The translator either knows the meaning of the idioms or looks them up in a Czech dictionary. There he finds: ''Vyzvonit [Informal] to divulge secret information,'' ''Byt v rejzi: [Informal] to be in a difficult situation.'' The idiomatic translation, of course, would be ''Sam has spilled the beans, and now we are in a jam.'' But, working at 5 cents a word and with the deadline looming, the translator does not search his memory for adequate phrases in English. He types, ''Sam has divulged our secret, and now we are in a difficult situation.'' Then he rushes on. Eventually he meets his deadline and comes up with a translation that contains no mistakes, for he is a conscientious worker. He also has a sense of English style, and so his editor, ignorant of the language of the original text, assures him that his translation ''reads well.'' Nobody in the 500 pages spills any beans; nobody pulls anybody's leg. The smooth text resembles a Van Gogh sunflower reproduced in black and white.

Two weeks before a visit to the United States, Prime Minister Milka Planinc says a faltering economy has brought Yugoslavia ''to the point of a rather dangerous limit of what people will tolerate.'' ''The most serious problem,'' the Government leader, 60 years old, said in an interview Friday, ''is that we have not been able to increase productivity as much as is needed, or to increase the standard of living.'' The inflation rate was nearly 80 percent for the first four months of the year; the unemployment rate of 15 percent is said to be Europe's highest; exports are stagnating. Determined Person Needed ''But we cannot allow ourselves to grow weary and give up, or return to uneconomic policies,'' she said.

There is no denying that West 23d Street is shedding its seedy image as Chelsea, the neighborhood around it, emerges as an area of choice for upwardly mobile Manhattanites. Still, it was a bold move for the developers of a new condominium at 118 West 23d Street to commission Der Scutt, the architect responsible for Trump Tower, to design their new building, which will go up on a block that is only begining to feel the impact of the area's gentrification.

IN the spring, sunrise comes to Long Island at about 6 o'clock, one hour after William Lieblein starts his workday at Port of Egypt Marine in Southold. Bulkheads and docks need to be repaired after a winter of ice damage. Hulls need to be scraped and painted. Plumbing and electric lines to marina slips need to be restored. And all of this needs to be done against the clock, according to Mr. Lieblein, if everything is to be ready in time for the summer boating season. It is a spring ritual that goes back to 1946, when Mr. Lieblein's father bought a small fishing station on Budd's Pond off Southold Bay and began building a boatyard and marina. A family tradition was built concurrently, rooted in what Mr. Lieblein called ''an emotional attachment to the land.''

After more than two decades of rejection and isolation, Fidel Castro is building new relationships in South America, dispelling many old suspicions and succeeding in dimming his image as a threatening revolutionary, many diplomats say. In the last year, Cuba has received a $600 million loan from Argentina. The right-of-center President of Ecuador, Leon Febres Cordero, made a formal visit to Cuba in April, and there have been signs that Uruguay, Peru and possibly Brazil may soon re-establish full diplomatic relations with Cuba. Cuba remains without diplomatic relations with Colombia, but Western diplomats and Cuban officials say that Mr. Castro has developed a personal relationship with President Belisario Betancur and that the two speak by telephone several times a week. In early May, Mr. Castro sent a shipment of medical supplies to Bolivia and 15 buses to Guyana. Both were gifts.