FOR LINGUISTS, it's like hitting a home run in the bottom of the ninth to win the World Series.
Terrence Kaufman and John Justeson struck that blast in 1993 when they cracked one of the planet's few remaining undeciphered writing systems - a hieroglyphic script from the mysterious Isthmian civilization, which occupied southern Mexico 2,000 years ago.
"It's one of the intellectual glories of the world, to be able to decipher an extinct writing system," said Brigham Young University linguist Stephen Houston.
But did their home run clear the fence? Houston and another researcher now say no. In fact, they call the translation "gobbledygook."
"Everything in my fiber tells me this is not a credible decipherment," Houston said.
He and Michael Coe, a retired Yale University archaeologist, launched their assault last month in the linguistic journal Mexicon, setting off fireworks in the small, usually genteel world of ancient-American linguistics.
"It's a tricky situation," said Martha Macri, a Mesoamerican linguist at the University of California, Davis. "Everybody knows each other."
Kaufman and Justeson, who have spent the past decade refining their work, have promised to demolish their attackers' case: "Their arguments against our methods and results are easily answered, and we will answer them in an appropriate scientific outlet," they wrote in an e-mail to The Sun.
But they have refused further comment, saying they don't want to debate the issue in the media.
What makes the dispute so difficult is that all four combatants are respected scholars.
Justeson, a linguist at the University at Albany in New York, is an expert on Mesoamerican writing systems. Kaufman, an anthropologist and linguist at University of Pittsburgh, spent decades on the Mixe-Zoquean languages of rural southern Mexico. Coe and Houston are prominent experts on Mayan writing.
"They're all brilliant," said George Stuart, president of the Center for Maya Research.
Unraveling ancient writing systems is much more than a linguistic party trick, researchers say.
"It's a window into the minds of the people who wrote it. That's something that archaeology alone can't give," said George Stuart's son, Harvard University linguist David Stuart, who has played a central role in decoding Mayan script.
Houston and Coe's case rests largely on a recently discovered jade mask whose back is carved with Isthmian writing. (The civilization is named for its location, on the Isthmus of Tehuantepec.) The mask, in a private collection, was unknown to researchers until Coe heard about it last year.
Coe and Houston realized that they could use the writing on the mask to test the accuracy of their colleagues' decipherment. "When you apply the supposed key, it turns out to be total nonsense and gobbledygook," said Coe.
In the Mexicon paper, they offer several examples, including passages they translate as: "Take he take cloth sun?" and "Your cloth he your take throne bludgeon."
The mask also contains about 20 previously unknown hieroglyphs, which suggests that many Isthmian symbols remain undiscovered. Working from a partial script, Houston says, is like reconstructing English using only half the alphabet.
They argue that Justeson and Kaufman's translations seem oddly banal. Most Mesoamerican texts deal with momentous characters and events: gods, kings, wars and dynasties.
"It's very strange that this script goes on and on about cloth and folding cloth," Houston said. "It's nothing that would make sense."
He and Coe also question the methods their colleagues used to decode the Isthmian hieroglyphs. Usually, they say, linguists decode a language with help from a "bi-script," a text containing a translation of the mystery language into a known language.
Archaeologist Jean-Francois Champollion, for example, unlocked ancient Egyptian hieroglyphics in the early 19th century by using the Rosetta Stone, a tablet containing identical text written in Egyptian and Greek.
But Kaufman and Justeson had no bi-script. Instead, they used Mixe-Zoquean as a touchstone. Because the language is spoken in the area where Isthmian artifacts have been unearthed, they argued that it was related to Isthmian. Coe and Houston say there is little evidence to support that theory.
In fact, until two decades ago, Isthmian was an almost total mystery. Only five or so examples of the script had been discovered, each with just a few lines of text. But in 1986, construction workers in southern Mexico found a huge stone tablet buried in the Acula River. The 4-ton basalt slab, 8 feet tall and 5 feet wide, was covered with Isthmian text - more than 400 signs.
Using the tablet, known as the La Mojarra stela, Justeson and Kaufman began to examine Isthmian through the lens of Mixe-Zoquean. In 1993, they published their work, which made the cover of Science magazine and received wide coverage in the popular press. Their discovery put them in the pantheon of decipherers, alongside great code-crackers such as Champollion and David Stuart.
Several ancient languages remain undeciphered, including Indus Valley Script, the writing system of a civilization that thrived more than 4,000 years ago in India and Pakistan, and Linear A, a language found on 3,500-year-old Cretan tablets.
On the Isthmian question, most linguists seem to be siding with Coe and Houston. "There are some serious flaws in their research," said Macri, who has compiled a catalog of Isthmian signs.
Some question whether Isthmian could be decoded so quickly. "Mesoamerican scripts are not built in ways that lead up to these 'eureka moments,'" said David Stuart. "They're pretty complicated."
He notes that after a century of work, dozens of Mayan scholars have translated only 80 percent of that script. While not certain that Justeson and Kaufman are wrong, he doubts much of their work.
Some researchers argue that because so few Isthmian texts have been discovered, cross-checking interpretations is almost impossible. Mayan researchers, by comparison, have been able to study thousands of texts.
"It could well be that we'll never be able to read it," Stuart said of the Isthmian text. "If Justeson and Kaufman are wrong, then I don't have much hope."