I learned how to talk dog really young. I had a German Shepherd mixed with a Flat Black Retriever (or was it the other way around?). He got huge. My mom was verbally aggressive with me, so my dog took that as a sign of her “attacking” me. He would growl and bark with his head lowered and hind up with a stiff tail at her. He was also food aggressive towards her. He never showed any of these signs to me, he did everything I said, never walked in front of me, never even mouthed me when we played in the yard. When ever he barked at me he would kinda do the same thing, bark, wave tail really fast, turn head towards the door. I always thought this meant he wanted me to go somewhere with him. Most times when he did this and we go outside, he would almost “go” like he was holding it all day waiting for me to get home from school. All dogs have their own personalities in addition to breed standards. I have an old Army friend with one of the most muscular pitbulls I’ve ever seen, and that dog is the goofiest thing I’ve seen outside of MAD TV.
From what I’ve read and seen (only once) Dashund’s are kinda like chihuahua dogs, small dogs with big personalities. When he barks, does it look like he’s straining (Like he’s barking so hard he has slight jerk movement)? If he’s barking that hard he’s “yelling” at you. If he’s barking and looking around with a stiff posture he thinks he’s the boss. When a dog “thinks” it’s the alpha it thinks it can tell you what to do and when. You stop dog dominance by continually practicing alpha tactics. There’s a ton of tips out there, but most dogs don’t need more than a couple, they learn incredibly fast. Like people already said, start doing things like food training and making sure your not following him. I know it’s hard, but until your done enforcing your status, don’t pick him up unless it’s an emergency. Picking up, petting, giving snacks for no reason, playing with him when HE brings a toy, and allowing him to walk in between your legs all enforce bad behavior. Also, even the dumbest dog wants to be mentally challenged, so start training him tricks, make him earn his stay, lol.