When I was in Barcelona it was explained to me how excruciatingly difficult the job of translation is, not only because of the texts themselves, but because the resulting translation must be able to work simultaneously in Spain, Argentina, Chile, Mexico – all slightly different in terms of certain usages.
I would add that Gibson's particular style is likely to be difficult to translate. As to whether Pattern Recognition will be harder or easier to translate than Neuromancer , that's an interesting question. Neuromancer was set in an imaginary future where certain types of technology had become all pervasive. The novel, is, however, more interested in the social consequences of the technology than the technology itself. Gibson had to invent the jargon and the language descibing this society himself. This jargon was to some extent made up, and to some extent drew on actual jargon of the early 1980s, but the translators no doubt had some liberty to either simply use the English word Gibson created in the foreign language or to make something up.
Now, however, we have the novel set in the present, which (at street level, anyway) looks rather Gibsonian. Gibson now has to use current, correct, jargon and slang (which he does), and this has to be translated into fairly current, correct, Spanish jargon and slang. And we then find the problem that he describes. The book is set in London, and the translation must be readily understandable in Argentina, and Chile. Presumably the book must be translated in such a way that it doesn't scream "Madrid" to Argentinians, as this might make the London setting less convincing.
As an Australian, though, I wonder if not too big a fuss is being made of this. English speakers don't read very much in translation in the first place, of course, but we read material in English and see television and film from throughout the Anglosphere. (Okay Iain, I've used the word). We become used to a great many dialects of English, and we learn to understand them. (Those of us who travel a lot learn to speak them to some extent, too. Certainly my use of the English language changes depending on the nationality of the person I am speaking to). Do Spanish speakers not learn and do this, too. I would think they would. When we do read in translation, we are normally reading books translated into standard British English or standard American English. And really, this doesn't bother me at all. If a Russian novel set in Moscow is translated into British English or American English, I am not going to notice distracted by which "regional" English it is, because I am completely used to this. (On the other hand, if a Russian novel set in Moscow is translated into Australian English, this will distract me a lot, because I am not used to it, even though I will have no trouble understanding it).
I don't know how much of this is peculiar to me, how much is true simply because I read a lot, and how much is true because I am an Australian and my native dialect, Australian English, is a relatively minor dialect of the language. Certainly, the text of American editions of books published in Britain or Australia is sometimes changed to make the English language in them better reflect American usage, although this isn't an especially big deal, so it my response may not be the universal one.
I suspect also in French there isn't much of a problem, and that when you translate a book into that language you are supposed to translate it into the French defined by the Academie Francaise . French speakers, be they in Paris, or Marseilles, or Montreal, or New Caledonia, or the Ivory Coast, are therefore no doubt used to translations into standard Parisian French.
Spainish no doubt is harder, due to the relative lack of importance of Spain in the the Spanish speaking world for many decades. Rather than a sphere of people containing the language with one or two political or economic centres to impose a standard, either de facto or de jure , the Spanish speaking world is sort of a many headed hydra. Still, however, the Spanish speaking world must have a standard. I would have thought that most serious readers in Spanish would be used to reading books translated into one (or several) standard forms of Spanish, even if these aren't terribly close to the forms they speak themselves.
As one of these dreadful monolingual anglophones, I'm just speculating, however. Other people's thoughts would be of interest.
Update: In my comments section below, Patrick Crozier askes if there is any real difference between Australian and British English, and if there is a difference between Australian and New Zealand English. I would argue yes in both cases.
Australian English is sort of a mixture of 19th century London and 19th century Ireland. It tends to be very colourful in its metaphors, and use of such devices as rhyming slang is quite common. (You will also find such things used by a much wider range of social classes than is the case in England. Also, rhyming slang is something the speaker is often unaware of, because when you use it, you don't use the word that rhymes. For instance, you might use the word "plates" to mean feet, and as you grow up you just think that it is a slang word and you don't realise it is an abbreviation of "Plates of meat" which rhymes with "feet". Australian English is full of things like that.
Plus, in the 20th century, Australian English has been much more likely to adopt American words than English words for new concepts: "truck" instead of "lorry", or "service station" instead of "garage". Australians did use "freeway" instead of "motorway" until a few years ago, but governments started using "motorway" instead when tolled motorways became common and people started complaining about having to pay for a road called a "freeway". (Another peculiar example is "chips". Australia has adopted the British word "chips" for what the Americans call "fries" and the American word chips for what the British call "crisps": that is we use the word "chips" for both. To avoid confusion, when you go into a store you ask for "hot chips" or "cold chips").
Plus of course we have a fair bit of vocabulary of our own. The shoes that are called "trainers" in Britain and "sneakers" in the US are called "joggers" in Australia. A "thong" in Australia is a flip-flop sandal. This occasionally causes embarassment when Australians use the word elsewhere. When I first visited the US and the UK in 1991, I was asked whether I wanted any "ketchup". I had never heard the word before: in Australia it is simply "tomato sauce". In the good old days of my childhood, it was merely "sauce", Australians being relatively unfamiliar with any other kinds of sauce. When I use specifically Australian vocabulary, I am often unaware that I am doing it until a foreigner fails to understand what I say. When talking about Buffy the Vampire Slayer I once described Willow as Buffy's "offsider". In Australia, the word is essentially a synonym for "sidekick", and I think the word comes from horsemanship. (Come to think of it, it is possible this meaning exists in Britain, too, because the people who failed to understand it were Americans).
Written Australian English is probably closer to British English than spoken Australian English, particularly in terms of spelling, because we are taught mainly British rather than American English in our schools.
New Zealand English is much more Scottish influenced and much less Irish influenced than Australian English. I am not familiar enough with New Zealand English to come up with examples off the top of my head, however.
Patrick also commented that the rise of Indian English is interesting to watch, and with this I concur, especially given that the contribution to English literature from India and the Indian diaspora is already large, and is obviously going to get larger.