When speaking to infants, mothers often alter their speech compared to how they speak to adults, but findings for fathers are mixed. This study examined interactions (N = 30) between fathers and infants (Mage ± SD = 7.8 ± 4.3 months) in a small‐scale society in Vanuatu and two urban societies in North America. Fundamental frequency (F0) and speech rate were measured in infant‐directed and adult‐directed speech. When speaking to infants, fathers in both groups increased their F0 range, yet only Vanuatu fathers increased their average F0. Conversely, North American fathers slowed down their speech rate to infants, whereas Vanuatu fathers did not. Behavioral traits can vary across distant cultures while still potentially solving similar communicative problems.