[andyjohnson0]

Multimeters that measure resistance and capacitance are relatively common, so it presumably wouldn't be impossible to build a talking version. Ensuring that diodes and electrolytic capacitors are correctly orientated would be a challenge though.

Another problem for building anything other than simple circuits is obtaining reference material (pinouts, current/voltage limits, etc) in an accessible form. I don't know how much help screen readers would be for high-density information containing diagrams and graphs.