I don’t know but I doubt it. Humans can think and act without using language. Think of an athlete, say a hockey player. While playing hockey there’s not time to verbalize your thoughts, and most of the thoughts are subconscious anyway.

For a dog, responding to a voice is probably little different than responding to a smell. Since dogs don’t talk there’s no need for them to formulate words in their minds.

I do think that dogs are consciously aware though. They communicate well with body language, and they can read our body language very well.

All animals, with vocal cords, communicate with sounds... We call these sounds, language... A dog doesn't "understand " the word but does associate the sound with a particular action...