What we don't know for certain is the word Luis Suárez used. Patrice Evra alleges it was racist and uttered at least 10 times. Suárez admits he did say something but nothing, for someone with his upbringing in Uruguay, he considers racist or deserving of the Football Association charges that will bring lawyers from Manchester United and Liverpool opposite one another in the coming weeks. Here lies the problem for the FA and the reason why they are thinking about bringing in a QC with specialist knowledge to oversee the case.

In ordinary circumstances, the FA would appoint a three-man panel consisting of an independent chairman, an FA councillor and someone described as a "football expert", meaning a former player or manager. The Guardian, however, has learned the FA may upgrade to a four-man commission because of the complexities of a case in which Suárez can, if necessary, point out he comes from a country where variations of the N-word are used very differently, and that it is actually quite common in Uruguay for men and women of all skin colours to have the nickname of El Negro or La Negra without any racist undertones.

Obdulio Varela, the 1950 World Cup-winning captain and one of the more famous footballers in Uruguayan history, is revered as El Negro Jefe (The Black Chief). Fernando Cáceres, who was in the Argentina squad at the 1994 World Cup, is another El Negro, as is Héctor Enrique, the Argentinian who played the pass for Diego Maradona to slalom through the England team in Mexico 1986. Then consider that Enrique, for example, is not even black, and it becomes even more confused.

Nor is this just a football thing. Rubén "El Negro" Rada is one of Uruguay's more successful musicians, appearing in a sitcom called La Oveja Negra (The Black Sheep) and with a compilation of his work entitled El Album Negro. Héctor Lescano, Uruguay's minister of sport and tourism, is known in politics as El Negro Lescano. The late cartoonist and writer Roberto Fontanarrosa and the late singer Mercedes Sosa were two others. Both were white.

Elliott Turner, the author of An Illustrated Guide to Soccer and Spanish, posed the question recently of whether, in the Suárez case, "Anglo racial linguistic norms really offer the right and only lens by which to judge". Turner, writing for The Run Of Play, said: "On a superficial level, in the Spanish language one can use the term negro or güero or moreno, with no negative connotation." Güero is white or light-skinned; moreno means brown or dark.

So is it all fairly innocent in the Spanish-speaking world? Not quite. "All language exists in context," Turner continued. "I'd say those terms only to family, friends or acquaintances. If you say the same term with anger in your eyes and hate in your heart, then its meaning can change 180 degrees." Like the time, perhaps, Luis Aragonés, at the time Spain's manager, referred to Thierry Henry as "negro de mierda" ("a black shit") in 2004.

This is where Suárez may find himself being interrogated. He and Evra were, after all, arguing at the time, so it would be difficult for the Liverpool player to make a case that it was merely an alternative to "mate" or "pal". Then there is the issue of whether ignorance should constitute any form of defence anyway. If a foreign visitor were stopped for driving on the wrong side of the road in England, would he get off simply because he could claim it was the norm where he was from? Suárez has lived in northern Europe since 2006, so an argument could be made he should have a decent grasp of what can and cannot be said outside South America and would be acceptable in one country but unacceptable in another.

Negrito is another prime example. It turns out this is not the word central to the Suárez-Evra case, but it does reveal a little more about the nuances of the Spanish language, translating as "little black guy" and such a common part of the vernacular that team-mates use it on each other as an affectionate term. Take the tweet Dani Pacheco, the Liverpool player on loan at Rayo Vallecano, sent to his Spain Under-21 colleague Thiago Alcântara via Twitter recently. "Negrito, enjoy yourself," it began.

Visitors to countries such as Uruguay and Argentina can, understandably, find it shocking if they are unaware of the semantics. "The key is the tone in which you say those words," Sebastián García, the South American football writer for Mundo Albiceleste, explains. "It can be extremely friendly to call someone negrito but it can also be very offensive."

In Brazil, it is negão, again with no racist connotation if none is meant. Other terms such as branco (white), moreno (dusky) and mulato (mixed race) are also commonly used in a non-offensive way. However, they can, too, be used in a racist capacity. Again, it comes down to context.

Another example is of Javier Hernández, now Evra's team-mate at United, in an interview on the Chivas Guadalajara website in 2007, where the Mexican is quoted complimenting "the goal of the Negrito", talking about his team-mate Omar Esparza. As García explains: "It all depends on the connotation, the way it is used, the tone, the intent."

Even then, different rules are in operation. When Carlos Tevez started out at Boca Juniors he was known as El Monito (The Little Monkey). Diego Perotti, the Sevilla player, goes by the same nickname, because his father, Hugo, who played with Diego Maradona at Boca, was El Mono (the suffixes -ito and -ita indicate a diminutive). Could a player in England, of whatever race, ever be called this?

If nothing else, it highlights that there may be shades of grey involved when it comes to deciding what is racist and what is not. But it is a complicated business and, in Suárez's case, this is why the FA has allowed him more time than usual to respond to the charges. Liverpool say he will vigorously protest his innocence and the striker has said his words were not an insult but just his own "way of expressing myself. I called him something his team-mates at Manchester call him, and even they were surprised by his reaction. There were two parts of the discussion, one in Spanish, one in English."

The delays have been frustrating for Liverpool, where they have offered Suárez their full backing, and also for United, where there is a feeling the dispute may have contributed towards Evra's erratic recent form. One of football's anti-racism bodies has complained behind the scenes that "people are tried for murder in less time". But the semantics and cultural issues are so complex it is not something the men in suits at FA headquarters can learn in a crash course. No date has been set for the hearing and, with legal teams to assemble, a row that began between two rival players on a football pitch on 15 October could very likely go beyond Christmas.