Spanish of Tarija
The Spanish spoken in the department of Tarija (south of Bolivia), commonly known as "español chapaco", is a linguistic mixture, a transitional variety between the Andean Spanish of Bolivia and the Spanish spoken in the Rio de La Plata region (called "español rioplatense"), strongly influenced by the "español camba" (the Spanish spoken in the Bolivian eastern lowlands) and by the Spanish spoken in north-western Argentina.
The accent of the "español chapaco" is similar to that spoken in the Argentine provinces of Jujuy and Salta. It is often described as melodious, with a distinctive musical intonation. Rural chapaca pronunciation is a mixture of those of the Andes and the eastern Bolivia; it includes the "seseo" (clear and strong pronunciation of the "s" sound), the use of the letter "j" replacing the letter "h" ("jaba" instead of "haba") or the letter "f" ("juerte" instead of "fuerte") and the exchange of the "o" for the "u" ("ahura" instead of "ahora", "agüelu" instead of "abuelo").
Its vocabulary is a blend of Colonial Spanish language (including the use of the pronoun "vos" instead of the pronoun "tú" (you), known as "voseo") with expressions from both the "camba" and the "rioplatense" Spanish (e.g. the use of the interjection "che" to call others attention), words from local indigenous languages (mostly those that refer to cultural features, animals and plants), Quechua and, to a lesser extent, Aymara terms, and several words characteristics of Tarija's region (e.g "churo", meaning "pretty, beautiful").
Thesis. "El español de Bolivia", by Gregorio Callisaya Apaza [es].