cry, honking of birds, droning of cicadas
唳 centers on loud, resonant animal sounds: the honking of birds and the droning of cicadas. The general sense of crying is an extension of these piercing calls.
唳 combines 口 (mouth) with 戾, which likely contributes the sound and may relate to a twisting or turning cry. The exact historical development is uncertain.
The mouth 口 on the left and the complex 戾 on the right suggest a mouth producing a loud, twisting sound. Picture a bird opening its mouth wide and letting out a honking cry that echoes.
For レイ, imagine a bird honking out a loud 'lay' sound: lay -> レイ, and the cry rings out from its mouth.
getting frightened even by a slight noise; hearing the enemy in every leaf that rustles; being afraid of one's own shadow