The scope of this page is late language emergence in children from 2 to 4 years of age.
See the Late Language Emergence Evidence Map for summaries of the available research on this topic.
Late language emergence (LLE) is a delay in language onset with no other diagnosed disabilities or developmental delays in other cognitive or motor domains. LLE is diagnosed when language development trajectories are below age expectations. Toddlers who exhibit LLE are referred to as "late talkers" or "late language learners." In this document, the term late talkers will be used.
Late talkers may present with expressive language delays only or mixed expressive and receptive delays. Children with only expressive delays exhibit delayed vocabulary acquisition and often demonstrate slow development of sentence structure and articulation. Those with mixed expressive and receptive language delays exhibit delays in language comprehension and in oral language production.
Some researchers distinguish a subset of children with LLE as "late bloomers." They posit that late bloomers catch up to their peers in language skills by 3 to 5 years of age. At onset, it is difficult to distinguish late talkers from late bloomers, as this distinction can be made only after the fact. However, there is some research to suggest that late bloomers use more communicative gestures than age-matched late talkers who remained delayed (Thal & Tobias, 1992; Thal, Tobias, & Morrison, 1991), thereby compensating for limited oral expressive vocabularies (Thal & Tobias, 1992). Research also indicates that late bloomers are less likely to demonstrate concomitant language comprehension delays when compared with children who remain delayed (Thal et al., 1991).
Late talkers may be at risk for developing language and/or literacy difficulties as they age. Late talkers who have receptive and expressive delays are at greater risk for poor outcomes than late talkers whose comprehension skills are in the normal range (Marchman & Fernald, 2013).
LLE may also be an early or secondary sign of disorders, such as specific language impairment, social communication disorder, autism spectrum disorder, learning disability, attention deficit hyperactivity disorder, intellectual disability, or other developmental disorders. In order to make a differential diagnosis, it is critical to monitor the global development of a child in domains that include, but are not limited to, cognitive, communication, sensory, and motor skills.