Defining regularity: Does degree of phonological and orthographic similarity among Polish relatives influence morphological processing?

In the present study we use a cross-modal (auditory-visual) priming paradigm to examine the influence on word recognition of phonological/orthographic variation between morphologically related nouns. We exploit particular characteristics of a highly inflected language, Polish, in which consonantal stem-boundary (portre/tɕ/e-portre/t/ ‘portrait’) and vocalic stem-internal (obr/ɔ/tem-obr/u/t ‘turn’) alternations occur. The impact of morphological relatedness was measured against an orthographic and an unrelated baseline condition. Invariant magnitudes of morphological facilitation arose across the two baseline conditions. More importantly, non-alternating as well as alternating morphological relatives showed robust facilitation. When comparing items featuring predictable stem-boundary change only and those featuring the stem-boundary and vocalic stem-internal changes, effects of morphological relatedness did not interact with degree of phonological/orthographic variation. We argue that morphological facilitation survives accross styles of alternation that vary from language to language.