give forth sound, make noise
嗁 centers on producing sound or noise, especially from a living source. It covers giving forth a cry, call, or audible signal.
嗁 combines 口 (mouth) with 虒, which likely contributes the sound. The character is associated with vocal sounds or cries.
A mouth 口 beside the complex 虒 shape: imagine a creature with a wide mouth giving forth a loud, echoing noise.
For テイ, picture a tea kettle whistling loudly: tea -> テイ, and the sound comes forth from the spout like a mouth.