Scientists have decoded "dog-directed speech" for the first time, and they say puppies respond to it.
Puppies reacted positively and wanted to play when researchers in France played them a tape of phrases like, "Who's a good boy?''
However, the international team of researchers found that adult dogs ignored this kind of speech.
When we talk to dogs, we often speak slowly in a high-pitched voice, similar to the way we talk to young babies.
The researchers think this way of talking may be our natural way of trying to interact with non-speaking listeners.
Prof Nicolas Mathevon of the University of Lyon/Saint-Etienne in France said pet-directed speech is similar to the way we talk to young infants, which is known to engage their attention and promote language learning.
"We found that puppies are highly reactive to dog-directed speech, in the absence of any other cues, like visual cues," Prof Mathevon told BBC News.
"Conversely we found that with adult dogs, they do not react differentially between dog-directed speech and normal speech."
The scientists recorded people saying the sentence: "Hi! Hello cutie! Who's a good boy? Come here! Good boy! Yes! Come here sweetie pie! What a Good boy!" as if they were speaking to a pet.
This was played back through a loudspeaker to dogs of all ages and compared with normal speech.
The researchers also found that human speakers use dog-directed speech with dogs of all ages even though it is only useful in puppies.