Latin America has just enough dialectal variation to identify a speaker’s regional or national background, but not enough to impede understanding between speakers of different variants. It is traditional among linguists to draw a distinction between highland and lowland varieties. By “highland” is meant the central plateau of Mexico, highland Guatemala, and the Andes. By “lowland” is meant the rest of Spanish-speaking Latin America: the Caribbean and Caribbean coast of Central and South America, the Río de la Plata and lowland Southern Cone, and the Pacific Coast from Chile to Mexico. Highland Spanish is characterized phonetically by “strong consonantism”: the retention of syllable-final /s/ and its voicing before a voiced consonant, the retention of intervocalic /b, d, g/ as fricatives, and no vacillation between /r/ and /l/. Lowland Spanish is characterized phonetically by “weak consonantism”: the aspiration or loss of syllable-final /s/, the loss of intervocalic /b, d, g/, and vacillation between /r/ and /l/.
This contrast between the two macrolects of Latin American Spanish is generally attributed to the differential intensity of colonization of the two zones. After 50 years of consolidation in the Caribbean, the Spanish moved quickly from 1550 to 1600 to occupy the centers of mainland population and wealth, those of the Aztecs in central Mexico, the Maya in highland Guatemala, and the Inca in the Andes. In the absence of any such rapid influx of population, some lowland areas took up to two hundred more years to attain an equivalent level of urban development.
As an urban bureaucracy was established to attend to the functions of the church, government, and university, a local linguistic form coalesced from the speech of the colonists to serve as the standard. There was a strong skewing towards Andalusia among the colonists, given that at least half of the men and most of the women were from Andalusia, the sailors manning the ships during the long passage to the Americas were from this region, and emigrants were required to complete the formalities of emigration in Seville – a process that could take up to a year. It follows that the standardization of a local urban prestige variant would reflect the mixture of Peninsular variants spoken at the time, but with a disproportionate representation of contemporary Andalusian. The Andalusian spoken during the first round of highland standardization was closer to Castilian in its preservation of consonants in weak positions, but as it evolved such preservation faltered, so that later rounds of lowland standardization incorporated subsequent phonological innovations. The global outcome is a pattern of change in which similar varieties are found at great geographic remove.