WHEN the new Chicano musical, "Zoot Suit," came to New York in late March, many easterners got their first exposure to the colorful gutty language of the barrio. They were hearing a schizolingual mixture of English and Spanish, such as "Hey, mano, mira la sexy redhead chambeando en la meat market with aquel butcher nalgon." ("Hey, man, look at that sexy redhead working at the meat market with that fatty butcher.")

Contrary to the general belief that most Chicanos and Puerto Ricans (those living here) speak conventional Spanish, the vast majority actually speak this amalgam of Spanish and English, which is known as "pocho," "calo" or "Spanglish."

There are varying degrees of this split language - from "maximum pocho," where there is a constant word-to-word shifting from Spanish to English, to "minimum pocho," where only a few Spanish words or phrases are used for added emphasis. In between there is "medium pocho," in which whole phrases are intermingled, as in: "Joe is a very smart lawyer, pero es muy estupido when he's dealing with women."

Although their born-in-Mexico parents and grandparents may still speak unadulterated Spanish, less than 20 percent of the Chicanos are truly fluent in Spanish. Consequently, when they go down to Mexico on vacation or business, they are apt to suffer culture shock, suddenly realizing that their pocho idiom is not understood by Mexicans and that they themselves do not always understand the madre lengua.

For example, they might ask a garage attendant to repair a taya ponchanda (punctured tire) and will be be told - often with a sneer - that it is a llanta desinflada. Indeed, taya ponchada is obviously closer to English than to Spanish, just as marqueta sounds more like "market" than does mercado. And such pocho words as yard (yard), brequas (brakes), caro (car), and rifa (reefer) are clearly more English than Spanish.

As recently pointed out by Prof. Rodolfo Alvarez, a noted UCLA sociologist, the pocho spoken in border towns has a more pronounced Mexican flavor than the pocho one hears in barrios farther north. "The degree of pochismo also reflects economic status and educational achievement," he adds, "but even the most highly educated lawyers, doctors or professors will occasionally lapse into pocho - particularly when talking about food or sex."

An untapped resource

Like several thousand other Chicanos, Prof. Alvarez is actually trilingual, having an easy command of English, Spanish and pocho. This particular group offers an invaluable resource to this country, especially in the field of diplomacy and other aspects of international relations. Unfortunately, until recently, it is a resource that has seldom been tapped by the Department of State. Thus, very few of our diplomats in Latin America - at any level - have been fluent in Spanish. The same can be said about our diplomats in other parts of the world.

The Russians, on the other hand, have numerous diplomats in Latin America who are remarkably fluent in Spanish and also well versed in the specific cultural milieu of the countries to which they have been assigned. In Havana, for example, they reportedly speak Cuban Spanish and can freely quote the local revolutionary poets; in Argentina, they adopt the special lilt of the Buenos Aires accent and casually alude to Borges' poems; like linguistic chameleons, they do likewise in other Latin countries.

But we seem less opportunistic in this regard. In the words of a French diplomat, "The United States is the most monolingual country in the civilized world." For example, very few American lawyers, doctors, architects or even college professors are fluent in any language except English, whereas, more than 50 percent of their counterparts in France are relatively fluent in a second language. This is also true of professional men and women throughout Enurope, Latin America, Asia and Africa.

Commenting on the linguistic competence of such foreigners, Prof. Christine Rossell of Boston University recently said, "We alone are content to remain monolingual, smugly relying on all other people to speak our language."

Further alluding to this language gap, an Iranian graduate student at Harvard told a friend that "I'm sure there wasn't one single American in the U.S. Embassy in Iran who could speak Farsi fluently. Consequently, even if your intelligence agents had tried to make contacts within the opposition, they would have had to rely on interpreters, many of whom are obsequious sycophants, who would tell the Americans only what they wanted to hear."

Since we have very few Iranian-Americans living here, this particular intelligence vacuum was understandable. Less understandable, says Prof. Alvarez, is our government's failure to take advantage of readily available bilingual Chicanos, Puerto Ricans, Cubans, Dominicans, et al. In this respect, many Latinos were puzzled and dismayed when President Carter failed to include certain prominent Chicanos in his entourage when he went to Mexico - particularly those who occupy high-level positions in his own administration.

Among the missing were: Dr. Ralph Guzman, the recently appointed deputy assistant secretary of state for Latin America; Abelardo Valdez, director of the Latin American division in the Agency for International Development; John Huerta, deputy assistant attorney general, an expert in international law and human rights; and - most surprisingly - Leonel Castillo, the commissioner of immigration and naturalization. Their presence on Carter's delegation would have been clear evidence of the president's avowed respect for the intelligence and special competence of the Chicanos he himself appointed. Moreover, their presence would have shown the Mexican president that Carter is presumably sensitive to the problems and concerns of millions of Americans of Mexican descent.

On a less lofty plane, any of the aforementioned Chicanos - all of whom are fluent in Spanish, English and pocho - could have told the president that the term "Montezuma's revenge" is not used by Mexicans. Turistas is what they call that ailment, leaving the mistaken impression that only tourists are afflicted. They also would have told Carter that such matters are not discussed at high diplomatic functions - but even Amy could have told him that.