唯读

• 口(mouth; opening)RADICAL
• 隹(short-tailed bird; bird with short tail)PHONETIC

A mouth uttering the sound of assent sounds like a bird chirping in response.

• 言(speech; words)RADICAL
• 賣(sell; vend)PHONO-SEMANTIC

Reading a book is using spoken words to 'sell out' knowledge to the listener.