Application of Cerebellar tDCS in Aphasia

The goal of this clinical trial is to learn if adding brain stimulation (cerebellar anodal tDCS) helps a computer-based therapy improve word-finding in Cantonese-speaking adults with aphasia after stroke. It will also check if the stimulation is safe and comfortable. The main questions it aims to answer are: Does real brain stimulation during therapy help people name pictures (both objects and actions) better and faster than fake (sham) stimulation? Are there different effects on naming nouns (objects) versus verbs (actions)? Do any participants feel side effects like tingling or discomfort from the stimulation? Researchers will compare real brain stimulation to sham (fake) stimulation while everyone gets the same 5-day computer therapy. Participants will: Do 60 minutes of computer word-naming practice every day for 5 days, twice (once with real stimulation, once with sham), with at least 2 weeks break in between Wear a cap with electrodes on the back of the head for the first 20 minutes of each session to receive either real or sham brain stimulation Name pictures on a computer before and after each 5-day block to measure improvement Report any feelings or side effects after each session