Fig. 1

Study flowchart for each subproject: word project (dark blue arrow), grammar (light blue arrow). Each subproject will include a sample of 180 participants between the ages 8 and 25 years. All 4 sessions, except the home training, will take place at the Donders Institute. In the word project (dark blue arrows), following the test battery during session 1, participants will return to the Donders Institute to learn the first half of the Finnish words and to become familiarized with the fMRI tasks in a mock scanner. During session 3, participants will begin by learning the second half of the Finnish words, outside the MRI scanner. Once the learning tasks have been completed, participants will perform the 4AFC test while in the MR scanner. Once outside the scanner, participants will perform the Cued Recall task. Finally, in session 4, participants will be familiarized with the artificial language learning task in the mock scanner, and then proceed to perform the artificial language learning task in the MR scanner. In the grammar project (light blue arrows), participants will receive the test battery and a short Icelandic word training during session 1. In the following session, participants will undergo a short grammar training, with half of the learned words, to familiarize themselves with the Icelandic grammar rules before they will perform the grammar judgment task in the MRI scanner. After this session, participants will undergo a 5-day training, ~ 30 min each day, to learn the Icelandic grammar rules further as well as some additional Iceland words that will not be used in the grammar training. Finally, in the last session, participants will complete the second grammar judgment task on the grammar trained and untrained Icelandic words. Besides the task-based fMRI data, additional MR data will be collected during both MRI sessions