The second factor is the medium of instruction used in schools.
This helps to build a person’s language repertoire. In our study, the second generation learns English and Mandarin at schools. While they grow up, they gradually find speaking English more confident than Mandarin or even Thai. This is because the secondary schools and university they go to use English as the medium of instruction and they have a lot of chances to use English. Therefore, the medium of instruction has a great influence on a person’s language choice.