1. Lesson 10: L, R, and Syllabic Consonants
The sounds /l/ and /r/ are formed with more movement of the speech organs
than most other consonant sounds. These two sounds are called liquids.
They are characterized by extensive movements of the speech organs from
one position to another. Unlike other consonants that are made with the
speech organs in a fixed position,liquids are sometimes described as vowel-
like consonants produced without friction. In English, /l/ is produced with the
tipof the tongue moving to or away from the tooth ridge, and the sides are
lowered so that the air goes out laterally. It is a voiced sound. The sound /r/
hardly seems to be pronounced in certain places except at the beginning of a
word or syllable. Most English speakers, however, pronounce it with both
sides of the tongue touching the back part of the tooth ridge and the back
teeth. The tip does not touch anything. The middle of the tongue, including
the tip, is lower than the sides, and the air goes out through the channel
formed between the middle of the tongue and the roof of the mouth. The
lips are slightly open. This liquid sound is made as the speech organs move to
this position from a vowel (are) or away from this position to a vowel (red). In
whatever direction it may end, it always begins by a motion toward the back
of the mouth, which is called retroflex.

2. As we know, /iy/, /ɪ/ , /ey/ , /ε/ and /æ/ are front vowels.
iy
ɪ
ey
ɛ
æ
The movements of /l/ and /r/, especially following a vowel sound, are
produced far in the back of the mouth. So it is more complicated to pass from
a front vowel sound to /l/ and/r/ than from a back vowel to either liquid. As
the tongue moves back from the position of the front vowel, it passes
through the middle, central zone where /ə/ is formed. In doing so, it
produces a centering glide that is heard as /ə/. We may say that,
WHEN A FRONT VOWEL IS FOLLOWED BY /l/ or /r/, AN INTERMEDIARY /ə/ IS INSERTED.
/iy/ + /ə/ seal /siyəl/ /ɛ/ + /ə/ well /wɛəl/
/i/ + /ə/ fill /fiəl/ wear /wɛər/
fear /fiər/ /æ/ + /ə/ shall /ʃæəl/
/ey/ + /ə/ tale /teyəl/
Prator, C. & Robinett, B. (1985). Manual of American English Pronunciation (3rd Ed). Orlando, FL: Harcourt Brace & Company