Abstract Language use in mountainous areas often exhibits special social dynamics. This contribution sketches some of the most salient patterns of language use in upland Southeast Asia ,the greater Himalayas, the Caucasus, the Central Andes, the New Guinea highlands, and touches upon the Alps and some highland areas of Africa and North America. Accumulated over long time, such patterns of use yield particular—often highly diverse, fragmented, and discontinuous—distributions of languages and language families in geographical space the precise characteristics of which also depend on prevailing local sociolinguistic and socioeconomic conditions. Generalization are still difficult since most observations are anecdotal rather than systematic: as far as language structure is concerned, languages spoken in mountainous regions are traditionally often attributed a “conservative” or “archaic” character, preserving inherited traits and patterns that are lost elsewhere; the inaccessibility of the terrain and the resulting relative social isolation are commonly invoked to explain this situation. More recently, mountain languages have also been claimed to feature peaks in the distribution of some typological properties, whether due to sociogeographical factors or, more controversially, even direct influences of the environment: ejectives, grammatical encoding of elevational or topographic information, and overall high levels of structural complexity.