Seriality in word reading: Kinematic insights into beginning and proficient readers

Learning to read is a crucial milestone in children's development that has a lasting impact on socioeconomic integration and professional success. In transparent orthographies (e.g., German) bearing consistent relations between graphemes and phonemes, beginning readers rely on sequential grapheme-to-phoneme recoding. This leads to early segmental accuracy but protracts word reading fluency. The present study revisited the seriality in word reading with innovative kinematic measurements of anticipatory coarticulation, an essential feature of speech fluency. We employed ultrasound imaging to investigate German beginning and proficient readers' tongue movements when reading aloud or repeating acoustically presented pseudowords. Using generalized additive mixed models, we show that, unlike adults, children in second and third grades initiated lingual gestures for target vowels substantially later in the Reading compared to the Repetition condition. Their extent of anticipatory coarticulation was therefore lower in the former than in the latter condition. The present study provides the first evidence that after 2 years of formal reading training, children still lack phonemic blending fluency when reading aloud. It further demonstrates the potential of kinematic measurements to detect fine-grained differences in phonological recoding not revealed by standard measures of reading fluency. Implications for models of oral word reading and its development, as well as developmental changes in phonological representations, are discussed. (PsycInfo Database Record (c) 2026 APA, all rights reserved).