Second language (L2) anxiety has been proposed to play a causal role in L2 achievement. However, most studies have failed to acknowledge confounding variables that may be relevant to the study of anxiety and L2 achievement or to investigate the causal effect of L2 anxiety using longitudinal data. For these reasons, we investigated the effect of L1 reading achievement, L2 aptitude, and L2 anxiety as covariates on the growth of L2 reading achievement across three time points. We used the latent growth curve model (LGCM) to estimate the growth trajectory of US secondary school students’ L2 reading growth in Spanish (N = 307) over three school years. The findings showed that students’ L1 reading achievement and L2 aptitude strongly and significantly predicted L2 reading achievement growth. However, L2 anxiety did not predict L2 reading achievement growth. Findings suggest that growth in L2 reading achievement depends on the language-related skills used for L1 reading and the language skills that comprise L2 aptitude, but not on anxiety. Similar to past cross-sectional studies, L2 anxiety related only to initial levels of L2 reading achievement, suggesting that anxiety reflects students’ initial experience of L2 reading but not their L2 achievement.

In this conceptual replication of Sparks and Dale ([2023]. The prediction from MLAT to L2 achievement is largely due to MLAT asessment of underlying L1 abilities. Studies in Second Language Acquisition, 1–25) utilizing a dataset previously reported by Sparks et al. ([2009]. Long-term relationships among early L1 skills, L2 aptitude, L2 affect, and later L2 proficiency. Applied Psycholinguistics, 30, 725–755.), L1 achievement scores over 1st–5th grades and L2 aptitude scores from the Modern Language Aptitude Test (MLAT) in 9th grade were examined as predictors of L2 achievement for U.S. secondary students completing L2 courses in 9th and 10th grades. The study’s focus was on the uniqueness and efficiency of MLAT with respect to measuring L1 achievement in predicting L2 achievement. All L1 measures and MLAT predicted L2 literacy and language, and L1 measures predicted MLAT scores. Word decoding was the strongest overall L1 predictor, though there was variation across the L2 measures. The unique contribution of MLAT was modest, as the majority of total prediction (77–86%) was due to L1 measures. The efficiency of MLAT in capturing predictive variance from L1 abilities was moderately high (median ∼73%) but variable across the L1 and L2 measures. Findings are generally consistent with those of Sparks and Dale (2023) showing that prediction from MLAT to L2 is largely due to MLAT’s assessment of L1 abilities, even though a substantial amount of L2 prediction-relevant L1 variance is missed by MLAT.

Despite the widespread use and effectiveness of the Modern Language Aptitude Test (MLAT) composite score in predicting individual differences in L2 achievement and proficiency, there has been little examination of MLAT subtests, although they have potential for illuminating components of L2 aptitude and the mechanism of prediction. Here we use regression commonality analysis to decompose the predictive variance from the MLAT into unique components for each subtest alone and for each possible combination of subtests (duos, trios, etc.) that may have shared variance. The results, from a longitudinal study of 307 U.S. secondary students during 2 years of Spanish learning, provide strong evidence for the role of literacy-related skills in all subtests and in predicting all L2 outcomes. These and other results support a view of L1 literacy and language skills leading to metalinguistic development, which in turn leads to stronger L2 aptitude and achievement.

Widespread use of the Modern Language Aptitude Test (MLAT) in L2 studies of individual differences implicitly assumes that L2 aptitude is a distinct cognitive facet. There is considerable evidence for prediction from L1 abilities to L2 learning. In this longitudinal study, L1-MLAT-L2 relations were examined in 307 US secondary students based on six L1 and six L2 measures of language and literacy, and the MLAT. Mediation and regression analyses revealed that each L1 measure individually predicted all L2 scores and MLAT; the L1 measures collectively substantially predicted MLAT scores; MLAT is a significant but moderate mediator of prediction from L1 to L2 scores; and prediction from MLAT to L2 scores is significantly and substantially due to variance in L1 abilities captured by MLAT. Overall, prediction from MLAT is due primarily to its functioning as a measure of L1 abilities, although substantial L1 variance which predicts L2 scores is not captured by the MLAT.

English as a foreign language (EFL) spelling was examined longitudinally three times (4th, 9th, 12th grades) during 9 years of EFL study among Hebrew first language (L1) students. The study examined the impact of L1 literacy variables including phonemic awareness, word attack, and spelling on EFL spelling and the relationship between EFL literacy variables and EFL spelling. Results showed that English spelling measured at earlier points strongly predicted later English spelling. L1 literacy skills measured in fourth grade were more significant than English word recognition in explaining end of ninth grade EFL spelling. Beginning of first year EFL letter knowledge in fourth grade predicted end of first-year EFL spelling. These results show qualitatively different L1 and EFL literacy abilities impacting EFL spelling at 4th, 9th, and 12th grades.