There are several creatures who cannot speak in our language, but still have the ability to understand what we are saying. There is also our beloved dog, "man's best friend". All of us owners of a dog (or more than one) know it well: just see how they react when we say "stroll?" or similar.
Good: a dog can exceed your expectations on the subject. A new study published in Applied Animal Behavior Science shows that dogs understand an average of 89 different commands. Simple things like "sit", "down" and "play". But it is an average. Some come to recognize over 200 different words and phrases. It is a "simplified" vocabulary equivalent to that of a two-year-old!
How a dog listens to you

About 90% of all dogs recognized at least 10 common words and phrases. The name of the dog (that practically everyone). Others like "sit down", "stay", "come", "ok", "no", "down", "wait" and so on. Researchers used continuous recognition of particular words and phrases to determine some degree of language understanding. Our four-legged friends seem to differ very much, not only in quantity but also in the types of words they respond to.
Another parallelism with children: after all it also depends on how many people talk to a dog, and for how long.
Of course, it's not just up to us. Scientists have collected very different dogs. They found that the dog's breed and tasks affect the number of words it recognizes. Professionally trained dogs can understand more words than those without training.
A nice research, sure, but also important
It is not just folklore. Continuing this research, the tools adopted in this could map many of a dog's skills and even act as a "professional advisor". That is, it could assess in advance the potential of each canid "candidate" for different professions (rescue, rescue, search, police, etc.)
And let's face it: understanding more about a dog's mind and how its perception of our language works is useful information that can be applied to the brains of other animals. Including us!