The official language is Spanish. Generally, most people speak Spanish using a local dialect, Castellano Rioplatense, which is subtly different from both the language of Spain and that of Central America. Most notably, the pronoun "tu" is replaced by "vos", and the you plural pronoun "vosotros" replaced with "ustedes", the latter being common throughout Latin America. Besides, there are separate verb conjugations, sometimes significantly different for irregular verbs in present tense and informal commands. Additionally, people from each city pronounce words differently too! In this way, people from Buenos Aires speak differently compared to those from Spain and other Spanish speaking countries; example: chicken in Spanish (pollo) is pronounced PO-zhO or PO-SHO by the "Porteños" (residents of Buenos Aires), with the SHsound harder than in Spanish; unlike most other Spanish speakers of South America who pronounces it PO-yo. However, all Argentinians learn standard Castillian Spanish in school, so while not the first language of choice, people would generally be competent enough to communicate.
Rioplatense Spanish is also heavily influenced by Italian, even frequently being mistaken for it, a result of the large influx of Italian immigrants. Hand gestures derived from Italy are extremely common, and many colloquialisms are borrowed from Italian (for example: instead of saying "cerveza", which means beer, youngsters find "birra" cooler, which is in Italian). Most locals can readily understand most Spanish dialects, as well as Portuguese or Italian (especially due to its similarity to the local Spanish). English is mandatory in high school and usually understood in at least a basic level in tourist areas. German and French can be understood and to some extent spoken by small fractions of the population. A few places in Patagonia near Rawson have native Welsh speakers. Words borrowed from aboriginal languages include: quechua, guarani, mataco, che, mate and others.
The interjection "che" is extremely common and means approximately the same thing as English "hey!". It can also be employed as a phrase known to someone you don't remember their names. Ex: "Escucháme, Che,...." Sometimes it is peppered throughout the speech, similar to the English phrase "yo," as in "What's up, yo?" Nonetheless, communication will not be a problem for any Spanish speaker.
Argentines will communicate with each other using lunfardo, a street dialect or slang. It is used together with Spanish by replacing nouns with their synonyms in lunfardo. As opposed to changing the original meaning, it just makes the phrase more colourful. An important aspect of lunfardo is that it is only spoken. For example, one knows the word dinero (money), but may use the word "guita" in order to refer to the same things. Lunfardo is composed of about 5,000 words, many of which do not appear in the dictionary.
Hey Big Balls
¡Che boludo! (poorly translated in the title) Che (used as injunctive, the root is indigenous) get's used a lot in casual speech ...between friends. It's why the Cubans nicknamed Ernesto Guevara, Che Guevara. It's a uniquely Argentine habit. Well Some Chileans use it, slightly differently, “Che huevón”
Don't be surprised if you hear some creative terms of endearment on the street. It's not uncommon to refer to one's friends as boludo ("big balls", which is a poor interpretation) or loco ("crazy"). If you read a bit about Lunfardo, you begin to see Argentines love to play with language, and love using nicknames. An essay by Santiago Kovadloff explains it well; A person who is overweight or fat is simply referred to by his friends as “flaco” (skinny) ...an intelligent person with a great talent to gain the respect of their peers is “un hijo de puta” (son a of bitch, which is a poor interpretation). It may seem counter intuitive to some, but friends do this as terms of endearment. They run the gamut. Negro (which has no negative connotation at all in Spanish) is a popular nickname regardless of a person's color. Loco is used interchangeably with boludo. Boludo can best be compared to how bollocks is used in Ireland: To a stranger it's an insult; to a friend it's a term of endearment.
This sort of blunt address is considered normal in Argentina. Try to take it lightly, as it is usually not meant to offend, but don't copy it. It takes time to understand the nuances of colloquialisms.
Although there's a community of descendants of Welsh immigrants on the Pampas, and Scots and Irish communities too, it's not these impoverished emigrant communities that have had the biggest influence in Argentina; that was from rich, monied investors that had the financial wherewithal to send their children to English boarding schools and universities.
Commonwealth English is certainly not an official language, but has historically been the variety widely used by the educated elite in Argentina.
Thanks to groups like the Argentine British Community Council (ABCC) it's possible that British expats may in fact feel more at home in Argentina than in Britain. Constantly arranging truly “British” events such as car boot sales, village fetes, fun runs and fundraisers, the ABCC see their duty as upholding the British tradition, which includes saying “please”, “thank you” and being on time! Argentina is the country with the biggest British community in Latin America, has many cities founded by Englishmen, and 80% of Buenos Aires' private schools are British. Argentina could have been, along with Australia, New Zealand and South Africa, the fourth British colonised country in the Southern Hemisphere!
Buenos Aires used to have the only Harrods store outside the UK and continues to have the most important and oldest English newspaper in Latin America, the Buenos Aires Herald. Just a few of the towns established by British settlers in the Buenos Aires Province of Argentina: Hughes, Rawson, Hudson, Hurlingham, Temperley, Banfield, O'Higgins, Brandsen, Parish, Fair, Barker, Bunge, Tornquist, Roberts, Gunther, Gahan, Abott, Anderson, and Warnes.
Few sights present as quintessentially British a scene as admiring the immaculately trimmed polo fields of the Hurlingham Club or watching a football match between St Andrews School and Balmoral College. The Anglophile can attain a pinnacle of perfection by taking afternoon tea while leisurely browsing through the local news in the Herald.