Spanish is the official language in the country and is spoken everywhere. Chileans use a distinct dialect called Castellano de Chile with a variety of differences in pronunciation, grammar, vocabulary and slang usage. Spanish-speaking foreigners won't have problems understanding it and will only think it sounds funny, but non-native speakers often struggle to understand it, even with years of practice. For example, Chileans tend to drop the "S" sound at the ends of their words. Instead, they replace that sound with an "H" sound (i.e. the word "tres" is pronounced "tréh"). On the other hand, standard Spanish is not the first dialect of choice, but people would generally be fairly fluent.

Here are two of the most common Chilean expressions:

• Huevón (pronounced usually as way-OHN) could be translated into different words according to its context. Originally a swear word meaning "jerk", it can be used also as "friend" or "dude".
• Cachar (pronounced ka-CHAR) comes from the verb "to catch" and means "understand". Also, is commonly used in a weird conjugated form as cachai'at the end of the sentences, similarly to "y'know", and in a colloquial manner it can also be used to mean sexual intercourse.

English is widely understood in large cities, especially Santiago, and to a much lesser extent in Valparaíso, Concepción or La Serena. English is now mandatory in schools, so younger people are far more likely to speak English than older people Most Chileans over age 40 are unlikely to speak English unless they are tourist industry workers.

Indigenous languages including Mapudungun, Quechua and Rapa Nui (in Easter Island) are spoken in Chile but only among indigenous people, who are less than 5% of the population. Many people identifying with one of these groups are not able to speak the language of their ancestors and speak only Spanish instead.

Many Chileans understand some French, Italian and Portuguese and also there are some German speakers, especially in the south of the country, where a lot of German migrants arrived in the second half of the 19th century and some around the time of World War II.