Nokia Syndrome
The noise made by an individual who does not know the answer to a question. The noise sounds similar to the vibration of a mobile phone when on Vibration Mode. There may be variations of tone in relation to situation.
Teacher: So what do you think about... (Asking the Student a difficult question).
Student: Mmmmmmmmmmm.... (Insert vibrating sound - Nokia Syndrome)
Student: Mmmmmmmmmmm.... (Insert vibrating sound - Nokia Syndrome)