Abstract
Expressions like English ago have been claimed to be among the most likely candidates for postposition crosslinguistically, and the reason for this has been conjectured to be diachronic. A few previous contributions notwithstanding, however, we still lack a typologically wider-ranging account of such temporal adpositions and adverbials and of how they develop. These are the main goals of the present article. Relying on a sample of 100 languages, it has been found that: (i) the structure instantiated in English by ago is far from universal and is geographically unevenly distributed; (ii) these expressions are indeed predominantly postposed, which does not hold for their mirror images for the future; and (iii) evidence from etymology, patterns of polysemy, and documented semantic extensions suggests that this asymmetry is the result of past and future markers having different diachronic sources.