Week 1 - Lessons 1 to 5 - /p/, /h/, /y/, /b/ and /l/
Week 2 - Lessons 6 to 10 - /v/, /d/, /r/ and /f/
Week 3 - Lessons 11 to 15 - /f/, /g/ and /m/
Week 4 - Lessons 16 to 20 - /n/ and /t/
