The Effects of Word Frequency and Word Predictability During First- and Second-Language Paragraph Reading in Bilingual Older and Younger Adults

We used eye movement measures of paragraph reading to examine how word frequency and word predictability impact first-language (L1) and second-language (L2) word processing in matched bilingual older and younger adults, varying in amount of current L2 experience. Our key findings were threefold. First, across both early- and late-stage reading, word frequency effects were generally larger in older than in younger adults, whereas word predictability effects were generally age-invariant. Second, across both age groups and both reading stages, word frequency effects were larger in the L2 than in the L1, whereas word predictability effects were language-invariant. Third, graded differences in current L2 experience modulated L1 and L2 word processing in younger adults, but had no impact in older adults. Specifically, greater current L2 experience facilitated L2 word processing, but impeded L1 word processing among younger adults only. Taken together, we draw 2 main conclusions. First, bilingual older adults experience changes in word-level processing that are language-non-specific, potentially because lexical accessibility decreases with age. Second, bilingual older adults experience changes in word-level processing that are insensitive to graded differences in current L2 experience, potentially because lexical representations reach a functional ceiling over time.