What does dumb as a dog he listened mean?

The phrase "dumb as a dog he listened" suggests that someone is passively listening without much understanding or response, much like how a dog might appear to listen attentively while lacking the ability to comprehend human language. It implies a sense of loyalty or obedience in listening, but also highlights a lack of intelligence or active engagement in the conversation. Overall, it conveys the idea of being attentive yet uncomprehending.