Mothers or sisters? The encoding of morphological knowledge

How is grammatical knowledge encoded in mental representations? While traditional accounts view grammar as a system of rules, construction-based theories assume declarative schemas – lexical entries with variables – as the locus of grammatical knowledge. Such schemas are evidently needed to encode productive patterns. However, morphological knowledge also includes relations between existing words, in patterns that cannot necessarily be productively extended. This contribution argues that such patterns can be encoded in two ways: by a ‘mother’ schema dominating the listed instances, or by ‘sister’ links between the instances themselves. Sister links are the more parsimonious option, since they do not require a superordinate layer in the constructional network. However, mother schemas can encode properties that sister links cannot. This paper aims to work out how the division of labour between sister links and mother schemas may be organized.