Reconstruction in syntax: Reconstruction of patterns
In syntax, reconstruction is limited to patterns, that is, repeated surface forms paired with a consistent function or distribution. Comparative reconstruction is illustrated with the example of the pattern of yes/no questions in Kartvelian languages and the core case marking pattern in the languages of the Nakh-Daghestanian family. The method involves setting up correspondences among patterns in languages known to be related. Determination of the ancestral pattern may make use of syntactic relics, dialect data, phonological correspondences, the principle of economy, and identification of internal or external sources of innovation, among other resources. Co-occurrence of all parts of a pattern provides the required safeguards in reconstruction of syntax, just as co-occurrence of all parts of a word does in reconstruction of phonology. Reconstruction of syntax is more likely to be successful in language families with less time depth and in ones with complex morphology reflecting the syntax, than in families lacking these characteristics.