If dogs understand some words, do they think we’re speaking absolute nonsense the rest of the time?

Like, my dog clearly knows walk, treat, stop and sit, but when I’m having a full conversation, he just tilts his head like I’m speaking in riddles. Do dogs think humans have this one ability to say the important stuff every once in a while and then spend the rest of the time making random mouth noises? I swear mine looks at me like, okay, buddy, you said the treat word five minutes ago, now you’re just babbling ha ha.