*"ACCH.txt" contains the data that were included in the analyses for accuracy and reaction times. *"Timestamps.txt" contains information about the timings in each trial; more specifically, (A) at when the trial ended (participant heard end of sentence, "TimeEnd") and (B) when the participants heard the auxiliary verb ("TimeAuxVP") (A) was subtracted from the time at which the participant responsded (StimSlide.RT) to calculate reaction times (B) was used to time lock the gaze data ***Other data files: (1) "CELF-4 Core Indexes and subtests Raw and standard scores.txt": this includes scores from the CELF-subtests (2) "Baseline measures summary": includes infomation from the CELF-4 but also age, Ravens' CPM, Renfrew PNT and CNRep (3) "Parental demographics.txt": includes information from parental questionnaires - relevant for all children (includes age, place of birth, information on language development, parental concerns, parental education etc) (4) "Bilingual exposure questionaire. txt": includes information about the bilingual children exclusively - this was used to estimate length of exposure (chronological age - age of first exposure to English), language dominance in terms of reported proficiency and quantity of exposure across a range of content (5) "Abbreviations.xlsx": this file contains an explanation of the labels used for the baseline measures (6) "Explanation.xlsx.": this file contains an explanation of the terms used in the parental questionnaire for the bilingual children used to establish thir dominance in terms of langauge use and proficiency. ***Files containing code (a) "Accuracy analyses _ children.R": mixed logistic regression models for accuracy (b) "RT analyses _ children.R": linear mixed effects models for reaction times (c) "Gaze data analyses _ children.R": spline regression models for gaze data -all files with analyses show how the data was prepared and how the background measures are merged is show for each analysis -for details on dependent and independent variables, please see paper