Children who use a pacifier or suck their fingers for more than three years may have greater risk of developing speech impediments, a study from Chile suggests.

Researchers evaluated the link between sucking behaviours and speech disorders among 128 children aged three to five from Patagonia, Chile.

Clarita Barbosa of Corporacion de Rehabilitacion Club De Leones Cruz Del Sur and colleagues asked parents about their infants' feeding and sucking behaviour and evaluated the child's speech.

Delaying use of a bottle until at least nine months seemed to reduce the risk of a child later developing speech disorders, the team reported in Wednesday's online issue of the journal BMC Pediatrics.

Children who sucked their fingers or who used a pacifier for more than three years were three times more likely to develop speech impediments, the team found.

"These results suggest extended sucking outside of breast-feeding may have detrimental effects on speech development in young children," Barbosa said in a statement, noting use of bottles and pacifiers has increased over the past few decades.

"Although results of this study provide further evidence for the benefits of longer duration of breast feeding of infants, they should be interpreted with caution as these data are observational."

Earlier studies by other researchers have suggested that sucking habits may affect the devopment of the mouth, jaw and teeth.

Other studies also suggest that breastfeeding may help infants develop co-ordinated breathing, swallowing and speech articulation.