In this study we investigated the role of interword spacing and its interaction with Arabic root frequencies by studying readers' eye movement patterns when they read Arabic sentences. Our eye-tracking experiment results did not show any significant evidence for the interword spacing effect on Arabic word processing, which concurred with the earlier work by Leung et al. (2021). On the other hand, we replicated an earlier experiment conducted by Hermena et al. (2020) on the effect of Arabic root frequencies on word processing. Contrary to their finding, our results showed that words which differed in root frequencies significantly modulated eye movement measures. This provided another support to the status of Arabic non-concatenative roots as a morphological unit.

This study investigates sentence processing in Standard Arabic (SA) by examining subject- and object-extracted relative clauses (SRCs and ORCs) through eye tracking. We test memory- and expectation-based theories of processing difficulty, and whether good-enough or noisy-channel processing leads to misinterpretations in ORCs. Our results find increased processing difficulty in ORCs, supporting expectation-based theories; however, this processing difficulty is not localized to the disambiguating region (relative clause verb) as predicted, but rather at the integration of the second noun phrase (relative clause NP). The findings support good-enough/noisy-channel processing theories, suggesting that readers may accept a noisy SRC interpretation of an ORC, and thus bypass integration costs at the RC NP.

This study investigated the extent to which varying interword spacing influences eye movement during reading in Arabic. Previous works conducted in Latin-script languages suggested that interword spaces facilitated word recognition. On the other hand, word recognition was inhibited when interword spaces were either removed or replaced by other characters (Rayner et al., 1998; Sheridan et al., 2013). We focused on the influence of interword spaces on reading Arabic which is characterized by the use of interword spaces and the position-informative allographic system. Based on an eye tracking experiment in which subjects read Arabic sentences presented in three levels of interword spacing and two levels of target word frequency, we found that eliminating interword spaces did not significantly inhibit reading, yet widening interword spaces exerted a facilitative effect. We argued that the effect of eliminating interword spaces was compensated by the ligating properties of Arabic letters during sentence reading, i.e. Arabic ligatures were position-informative which provided sufficient visual cues for word recognition regardless of the presence of interword spaces.