I think dogs understand single words.
You don’t have to use entire sentences when it comes to dogs.
I had a n Irish Setter,a brilliant field dog hunting upland game. At the age of 7 I counted his vocabulary, he understood about 60 words. Often he would try to talk
mumbling away and moving his jaw, often doing it when something was bothering him, so I payed attention.
I miss that pooch , he passed at the age of 13.
I think they understand voice tone and facial expressions as well.
When we tell our husky simmie are you hungry he comes running same with do you want to go outside