בֵ
Tsere (צֵירֵי, tsey-rey), is a long E-Class vowel.
It is represented by a two side-by-side dots beneath the letter, and sounds like the “a” in lay.
When the tsere+yod combination occurs, the tsere takes on the responsibility of making the vowel sound and the yod (acting as a matre lectionis may be treated as quiescent.
See: niqqud