无话可说

• 一(one; initial)ASSOCIATIVE
• 尢(disabled person; insufficient)ASSOCIATIVE

From the beginning there was a shortage, so 無 means 'nothing at all'.

• 言(speech; words)RADICAL
• 舌(blade; tongue)PHONO-SEMANTIC

Speech is what is created from the tongue.

• 口(mouth; opening)RADICAL
• 丁(man; adult male)PHONETIC

A mouth uttering words of approval with a sound like "ding" gives you the character meaning "can" or "able."

• 言(speech; words)RADICAL
• 兌(exchange; joyful)PHONETIC

Speaking is using words to exchange with each other.