Eye fixations, speech rate and bilingual digit span: numeral reading indexes fluency not word length.

The present study examined whether the reading of language-neutral stimuli, as numerals are, at maximal speed by bilinguals indexes processes related to fluency rather than differences in articulation time between languages. We tested two groups of bilinguals that spoke the same languages (Finnish and Swedish) but whose mother tongues were different and obtained measures of Arabic numeral processing by monitoring eye movements. These measures were contrasted with articulation and numeral reading estimates of word length. The results indicated that Finnish- and Swedish-dominant bilinguals had shorter gaze durations and shorter reading times in their respective dominant languages, whereas both groups articulated digits faster in Swedish than Finnish. The Swedish-dominant group had a larger digit span in Swedish, whereas digit span was marginally greater in Finnish than Swedish for the Finnish-dominant group. The finding that numeral reading was influenced by cognitive loads independent of articulation, thus, moderated the view that bilingual digit span effects are mediated exclusively by variation in word length between languages.