Caland system

The Caland system is a set of rules in the reconstructed Proto-Indo-European language which describes how certain words, typically adjectives, are derived from one another. It was named after Dutch Indologist Willem Caland (1859–1932), who first formulated part of the system.

The cognates derived from these roots in different daughter languages often do not agree in formation, but show certain characteristic properties:

• Adjectives are formed using zero-ablaut ro-stems (i.e., word stems ending in *-rós), u-stems, or amphikinetic nt-stems.
• Adjectives are sometimes formed using i-stems, especially in the first part of a compound.
• Corresponding stative verbs in *-eh₁- often exist.