Changes of linguistic competence were assessed with the Aachen Aphasia Test in 18 aphasic patients across 8 weeks of spontaneous recovery, 8 weeks of intensive language therapy and again across 8 weeks without therapy. At the start of intensive therapy, neuropsychological tests were administered to measure praxis, executive functions, working memory, episodic memory, and semantic memory. Initial level of linguistic competence correlated with recovery of aphasia across all periods. Tests requiring recall of non-verbal information from either episodic or semantic memory correlated with success of intensive therapy but not at all with spontaneous recovery. Possibly, measuring the ability to recall non-verbal information acted as a detour to assess memory capacities necessary for the learning of linguistic skills and knowledge independently of the influence that aphasia itself exerts on the explicit learning of linguistic skills and knowledge contributes to the success of language therapy but not to spontaneous recovery.