lecturer 1 [r] in isolation lecturer 2 [r] in isolation lecturer 3 [r] in isolation
Based on Maciołek & Tambor (2012)
Voiced: the vocal folds are in contact, the air coming from the lungs causes them to vibrate.
Alveolar: the front part of the tongue touches the alveolar ridge.
Non-palatalized: the middle of the tongue is in a neutral position, it does not take part in the articulation.
Trill: the sides of the tongue lie against the inner surface of the upper teeth and gums, the tip of the tongue moves away from a neutral position and hits the alveolar ridge. There can be one or more such taps.