The fruit of their toil is a nearly 4,000-page tome in two volumes presented Thursday, with yet another to come out next year.
It was produced by the Spanish Royal Academy and 21 sister organizations in Latin America and other countries where Spanish is spoken, such as the United States and the Philippines, and has taken them 11 years to compile.
The book is billed as a sort of linguistic map that painstakingly documents today's Spanish in all its richness -- there are nearly 20 ways to say ballpoint pen, for instance -- and how it varies from country to country, or within one, and even from one social class to another.
Indeed, while English speakers face the perennial 'you-say-tomato, I-say-tomahto' dilemma, Spanish is also chock full of variety in pronunciation, vocabulary and the ways sentences are constructed.
The biggest difference from the existing grammar, which dates back to 1931, is that the new book reflects how the language is spoken where most Spanish-speakers live: Latin America.
In Puerto Rico, for example, it acknowledges -- and respects -- the fact that subject and verb in a question are often switched around to an order resembling that of English. So the question "Adonde vas tu?" -- where are you going? -- becomes "Adonde tu vas?" in the U.S. territory.
"Here are all the voices, all the ways of speaking, coming together in a grand polyphony," Victor Garcia de la Concha, president of the Spanish language academy, said at Thursday's ceremony. "This book comes from the people, and it is to the people that it reaches out."
The new grammar book does not attempt to set cut-and-dry dogma on what is correct and what is not, making instead recommendations as to what the language gurus generally accept to be proper Spanish.