Abstract: Morphology is concerned with the structure of words. Traditionally, morphological operations are divided into word formation, that is, the creation of new words with new meanings, and inflection, the process by which grammatical information is realized on a word. While all morphological operations can be affected in language disorders, research has focused on inflectional deficits. One reason for this is that inflectional morphology is widespread in the languages of the world and when present in a language is likely to surface in every utterance. Deficits with inflectional morphology are, therefore, easy to identify, by listening to the spontaneous or probed speech production of affected speakers. Also, inflection is situated at the interface of morphology, syntax, and phonology. While inflection creates grammatical word forms and thus is part of morphology, the grammatical information added typically exerts effects on other constituents in a phrase/sentence and hence is effective in syntax. Moreover, the choice between different inflectional allomorphs might be phonologically determined and the inflected word form must adhere to the phonological constraints operative in a given language. In addition, the production and perception of inflectional morphemes are dependent on articulatory and perceptual abilities. These interrelations make inflectional morphology vulnerable to language deficits that can target any of these components: perception, articulation, phonology, morphology, or syntax. Not surprisingly then, deficits with inflectional morphology are a hallmark of language disorders and have been observed in practically every acquired or developmental language disorder that has come under the scrutiny of clinical linguists. To summarize the wealth of research that has been conducted on inflectional deficits across different languages and different syndromes would go far beyond the limits of this chapter. Rather, its aim is to highlight factors that affect the occurrence and shape of inflectional deficits across disorder syndromes and to sketch the gist of proposals that have been advocated to account for inflectional deficits.

Penke, Martina (2024): Inflectional morphology and language disorder. In: Nicole Müller, Martin Ball & Liz Spencer (eds.): Handbook of Clinical Linguistics, Second Edition. Wiley, 201-214. https://doi.org/10.1002/9781119875949.ch15.