Research finds that young children use private speech most when:

1. Private speech helps children guide and regulate their own behaviour. 2. The more self-regulation a situation demands, the more children use it. 3. Children use more private speech on harder tasks. 4. They also use more when working without a teacher's or parent's help. 5. Studies found preschoolers least likely to use private speech with a teacher present. 6. So it peaks when the task is more difficult. **Why the other options fail:** - Easy tasks need little self-guidance. - A teacher nearby lowers private speech. - Help from an adult also lowers it, since children use more private speech when working without such help. _Source: Wikipedia, "Private speech", section "Behavioral self-regulation and emotion regulation" (revision 1378894484)_