Some experimental evidence shows that wolves are more sensitive to lower speech and dogs are more sensitive to higher speech.
How do pets understand human language
They use visual, auditory and olfactory communication channels, so it is not difficult for them to understand each other.
We can definitely say that cats and dogs understand human speech in the language that their owner speaks.
How do dogs hear human speech
Scans have shown that when dogs hear familiar words like "good boy," their left brain is activated.
When they hear a laudatory intonation, their right hemisphere is activated - no reaction was noticed to a neutral tone of voice.
What words do cats understand
On average, cats understand 20 to 50 human words. But at your level.
They do not know what a single word means, they just understand what will follow it - that's why they react.
Usually such words are associated with food, games, affection - and the cat remembers them after repeated repetitions, as dogs remember commands.