A critical period for second language acquisition: Evidence from 2/3 million English speakers - Hartshorne, JK; Tenenbaum, JB; Pinker, S (2018)
longitudinal; evidence grade C

Critical Period Claim Revisited: Reanalysis of Hartshorne, Tenenbaum, and Pinker (2018) Suggests Steady Decline and Learner-Type Differences - van der Slik, F; Schepens, J; Bongaerts, T; van Hout, R (2022)
critique; evidence grade C

No evidence that age affects different bilingual learner groups differently: Rebuttal to van der Slik, Schepens, Bongaerts, and van Hout (2021) - Hartshorne, JK (2024)
critique; evidence grade D

Critical Evidence: A Test of the Critical-Period Hypothesis for Second-Language Acquisition - Hakuta, K; Bialystok, E; Wiley, E (2003)
longitudinal; evidence grade C

Critical period effects in second language learning: The influence of maturational state on the acquisition of English as a second language - Johnson, JS; Newport, EL (1989)
quasi-experiment; evidence grade D

The Critical Period Hypothesis in Second Language Acquisition: A Statistical Critique and a Reanalysis - Vanhove, J (2013)
critique; evidence grade C

Age of Onset and Nativelikeness in a Second Language: Listener Perception Versus Linguistic Scrutiny - Abrahamsson, N; Hyltenstam, K (2009)
quasi-experiment; evidence grade C

Linguistic dissimilarity increases age-related decline in adult language learning - Schepens, JJ; van Hout, RWNM; van der Slik, FWP (2022)
longitudinal; evidence grade C

The Critical Period for Language Acquisition: Evidence from Second Language Learning - Snow, CE; Hoefnagel-Hohle, M (1978)
longitudinal; evidence grade C

Symmetries and Asymmetries of Age Effects in Naturalistic and Instructed L2 Learning - Munoz, C (2008)
longitudinal; evidence grade C

From Early Starters to Late Finishers? A Longitudinal Study of Early Foreign Language Learning in School - Jaekel, N; Schurig, M; Florian, M; Ritter, M (2017)
longitudinal; evidence grade C

Effects of an early start in learning English as a foreign language on reading and listening comprehension in Year 9 - Porsch, R; Schipolowski, S; Rjosk, C; Sachse, KA (2023)
longitudinal; evidence grade C

Starting Age Overshadowed: The Primacy of Differential Environmental and Family Support Effects on Second Language Attainment in an Instructional Context - Pfenninger, SE; Singleton, D (2019)
longitudinal; evidence grade C

Is bilingualism related to a cognitive advantage in children? A systematic review and meta-analysis. - Gunnerud, HL; ten Braak, D; Reikeras, EKL; Donolato, E; Melby-Lervag, M (2020)
meta-analysis; evidence grade C