This project uses functional transcanial Doppler sonography (fTCD) to investigate lateralisation of L1 and L2 in bilingual adults. There are two studies. ## Study 1: French-English and German-English Bilinguals ## Study 1 tested highly proficient French-English or German-English bilinguals. This data was acquired and previously written up by Grabitz & Bishop (2016). The current reanalysis will be published as an updated version of this publication. Participants performed a covert phonological word generation task in both their first (L1, French/German) and second (L2, English) languages. ### Study 1 fTCD Data ### Data was collected from 26 participants. The raw fTCD data is available in .exp format. There are two files per participant: one for L1 (labelled as F for French or G for German), and one from L2 (labelled as E for English). The file Study1_filelist.xlsx records which fTCD trials should be included/excluded in the analysis. ### Study 1 fTCD Analysis ### The fTCD data is analysed using two scripts: - Study1_analysis1.R: this script reads in the raw fTCD data and the information in Study1_filelist.xslx and calculates LI values for each participant. The results are stored in Study1_resultsL1.csv and Study1_resultsL2.csv - Study1_analysis2.R: this script reads in the results from analysis1 and identifies outlier datapoints that will be excluded in the final group analysis. ## Study 2: Japanese-English Bilinguals ## Study 2 tested Japanese-English bilinguals with more variable proficiency. This data was acquired by Miho Sasaki and Heather Payne at UCL. Participants performed overt phonological and semantic word generation tasks in L1 (Japanese) and L2 (English). ### Study 2 fTCD Data ### Data was collected from 26 participants. The raw fTCD data is available in .exp format. There is just one file for each participant: the different languages and tasks are encoded using different numbers for the trial markers. The file Study3_filelist.xlsx records which fTCD trials should be included/excluded in the analysis. ### Study 2 fTCD Analysis ### Like Study 1, the fTCD data is analysed using two scripts: - Study2_analysis1.R - Study2_analysis2.R ## Final Analysis After the LI values are calculated for Study 1 and Study 2, the R Markdown script Bilingualism_writeup.Rmd performs the group analyses as shown in the manuscript.