What is in a morpheme? Theoretical, experimental and computational approaches to the relation of meaning and form in morphology

Speakers use words to communicate. This may seem obvious, but obvious things can also be the most difficult to explain. Because what sets one word (or in sign languages, one sign) apart from another? Words have some kind of internal structure, but this structure can only be discovered by comparing words with one another. And while words and their subparts consist of phonemes, the latter are not associated with meanings themselves. Thus, understanding how exactly meaning and form relate in morphology is a non-trivial task. In this introductory article to the special issue, we would like to elucidate a specific view of morpheme-based morphology by reconsidering the relationship between form and meaning in morphology.