A randomized control intervention study was conducted to evaluate the effects of the highly structured Heidelberg Parent-Based Language Intervention (HPLI). The outcomes of 43 children (n = 23 intervention, n = 20 control) who had been identified as late talkers during routine developmental check-ups carried out in pediatric practices at the age of 2 years were examined at 4 years 3 months of age. To address these results, we used standardized instruments to assess language and memory performance. At the age of 4 years, expressive language abilities did not differ as a function of the early language intervention. Results in language comprehension, phonological memory, and episodic buffer were significantly better in the intervention group than in the control group. These findings demonstrate the long-term effectiveness of the parent-based language intervention HPLI, and have practical implications for dealing with children with specific expressive language disorder (SELD).