The latest evidence, published Wednesday, suggests that long-term pacifier use, thumb-sucking and even early bottle use increases the risk of speech disorders in children. The study was published in the open access journal BMC Pediatrics. The study looked at the association between sucking behaviors and speech disorders in 128 children, ages 3 to 5, in Chile. Delaying bottle use until the infant was at least 9 months old reduced the risk of developing a speech disorder, researchers found. But children who sucked their thumb, fingers or used a pacifier for more than three years were three times as likely to develop speech impediments. Breast-feeding did not have a detrimental effect on speech development. The authors of the study said that other research suggests that use of a pacifier or thumb-sucking for less than three years also increases the risk of a speech problem. The sucking motion may change the normal shape of the dental arch and bite. Breast-feeding, however, seems to promote positive oral development. 'The development of coordinated breathing, chewing, swallowing and speech articulation has been shown to be associated with breast-feeding. It is believed that breast-feeding promotes mobility, strength and posture of the speech organs,' the authors wrote. 