The impact of orthographic complexity on handwriting and typing in a shallow orthography

Handwriting and typing involve distinct motor processes that influence how orthographic information is managed during word production. This study investigated how orthographic complexity—specifically digraphs—affects writing execution in Italian, a shallow orthography, in both adults (N = 36, Mage = 23.58) and adolescents (N = 36, Mage = 14.75). Participants completed a dictation task involving 32 stimuli (words and pseudowords) containing a digraph, writing them in both handwriting and typing modalities. During writing, interletter intervals (ILIs) were measured at three critical points: before the digraph (Syllable-Boundary-ILI), within the digraph (Digraph-ILI), and after the digraph (Post-Digraph-ILI). Results showed that across modalities and age groups, the Syllable-Boundary-ILI was longer than the other ILIs, indicating pre-planning of the following orthographic sequence. In handwriting, ILIs progressively shortened across the three positions, whereas in typing, ILIs remained constant within and after the digraph. Adolescents exhibited greater difficulty in initiating the digraphs and the subsequent vowels, particularly in typing, the modality they were less experienced with. These findings suggest that handwriting supports more cohesive motor planning of orthographic units, while typing relies on a more discrete approach, especially in younger, less skilled writers.