BACKGROUND: Global aphasia is a severe communication disorder affecting all language modalities, commonly caused by stroke. Evidence as to whether the functional communication of people with global aphasia (PwGA) can improve after speech and language therapy (SLT) is limited and conflicting. This is partly because cognition, which is relevant to participation in therapy and implicated in successful functional communication, can be severely impaired in global aphasia. Cognitive treatments that aim to improve functional communication for people with aphasia do exist, but few have been trialled with PwGA and no studies have robustly demonstrated gains. AIM: This study aimed to explore the effect of a novel non-linguistic cognitive intervention on the functional communication skills of PwGA. METHOD: A non-linguistic intervention, developed to target cognitive skills underpinning functional communication, was delivered to six participants three times weekly for up to 6 weeks (depending on the rate of progression through the intervention programme). All participants met the criteria for global aphasia following screening with the Western Aphasia Battery Bedside Record Form. A multiple baseline case series design was employed to investigate changes in functional communication using the American Speech and Hearing Association Functional Assessment of Communication (ASHA-FACS). Secondary outcome measures were auditory comprehension and informal tests of non-verbal cognition. Statistical analyses of change after intervention were performed using the Wilcoxon signed-ranks test and weighted statistics. RESULTS: Participants completed the intervention programme in an average of nine sessions. Four out of six participants made statistically significant gains in functional communication as measured by communication independence (amount of assistance or prompting required) on the ASHA-FACS. Five of six participants made statistically significant gains in non-verbal semantics, two in non-verbal reasoning and two in auditory comprehension. CONCLUSION: The findings provide preliminary evidence that a non-linguistic cognitive intervention delivered with a dose replicable in clinical practice can improve functional communication and non-verbal cognition in some PwGA. This finding contrasts with much existing evidence suggesting that improvements in global aphasia can be achieved only after intensive or prolonged input over many years. WHAT THIS PAPER ADDS: What is already known on the subject People with global aphasia (PwGA) have the potential to make impairment level gains after intensive or prolonged speech and language therapy (SLT). However, evidence of functional communication gains is limited. Cognition plays an important role in functional communication, particularly the ability to switch to alternative means of communication and switch modalities. What this study adds Contrary to many previous studies, the findings indicate that PwGA can benefit from SLT and make functional communication gains with a relatively low dose of intervention. The findings highlight cognitive skills that appear relevant to basic functional communication abilities in PwGA. These are: attention, visual perception, semantics and non-verbal problem solving. What are the clinical implications of this work? This work suggests that clinicians should offer cognitive, non-linguistic interventions to PwGA and consider delivering intervention using little to no verbal language.