lecturer 1 [f] in isolation lecturer 2 [f] in isolation lecturer 3 [f] in isolation
Based on Maciołek & Tambor (2012)
Voiceless: the vocal folds are separated, not vibrating, the air flows freely between them.
Labiodental: the lower lip gets closer to the upper teeth.
Non-palatalized: the middle of the tongue is in a neutral position, it does not take part in the articulation.
Fricative: there is a narrow passage between the articulators, the air from the lungs hits the edge of the passage and creates noise.