Approximants are
speech sounds that involve the
articulators approaching each other but not narrowly enough nor with enough articulatory precision to create turbulent airflow. Therefore, approximants fall between
fricatives, which do produce a turbulent airstream, and
vowels, which produce no turbulence. This class of sounds includes
lateral approximants like (as in
less), non-lateral approximants like (as in
rest), and
semivowels like and (as in
yes and
west, respectively).