Mothers tend to engage in "babytalk" with their young children while fathers treat them more like grown ups, scientists have found.
The two approaches are thought to complement each other to help a child's language learning.
Researchers used speech recognition software to analyse the way mothers and fathers spoke to their pre-school children.
Distinct differences were seen between the two. Mothers used a voice that was higher and more varied in pitch than when having a conversation with other adults - characteristics common in "babytalk".
In contrast fathers used intonation patterns more similar to the ones they used when they spoke to their adult friends and colleagues.
Babytalk, or "motherese", is believed to promote bonding because its attention-catching cadences and exaggerated vocal features are attractive to babies and young children.
But this does not imply that fathers are failing to engage with their offspring, said lead scientist Professor Mark VanDam, from Washington State University in the US.
"We think that maybe fathers are doing things that are conducive to their children's learning but in a different way," he said. "The parents are complementary to their children's language learning."
By speaking to their children more like adults, fathers may help their children deal with unfamiliar speech and provide a "bridge" to the outside world, according to the researchers.
Less frequent use of classic babytalk did not prevent fathers modifying their speech in other ways, for instance by using different vocabulary or changing the volume or duration of what they were saying.
The age and sex of the child might also influence the father's interactions, said Prof VanDam.
The findings were presented at the 169th meeting of the Acoustical Society of America in Pittsburgh.