Derivation in the lexicon: the case of Esperanto

This study takes Functional Discourse Grammar (FDG) as its theoretical framework, and applies to the phenomena under study the FDG terminology, which may differ from what many readers are used to. Esperanto has an agglutinating morphology. Its words are built on stems which are associated with contentive lexemes in a flexible system of parts of speech. The language has an elaborate stock of lexically dependent morphemes (roots in FDG) for lexeme building. Many basic words are stem-root combinations in Esperanto. The roots applied in them also appear in complex structures, and can be reordered and interchanged easily to produce different complex stems. For this reason, derivation is taken to be hosted in the lexicon. The lexicon must contain a highly developed procedural knowledge component, of which the derivation system is assumed to be a part. Some of the suffixable roots have homonymous variants that define grammatical processes. The combinatorial freedom of roots provides for a lexical expansion tool which is easy to handle, but not without complications. Problematic is the (in)transitivity of lexemes destined to verbal encoding, when applied in an environment that is not naturally theirs. This phenomenon is known to be an important source of mistakes among speakers of the language. It is argued that the lexicon of Esperanto speakers contains paired transitive and intransitive representations of the most current lexemes of this category. The study aims at providing support to better understand the mechanisms at work inside the lexicon and at the interface between the lexicon and the grammar of agglutinating languages.