If you are just looking for a single input and output your simplest solution would be one of those tour guy battery powered speaker and mics like this one

If you want to do something more complex a mic and some inputs prerecorded inputs. You need some sort of headset mic and then you could set up sfx through an arduino. For the speakers you probably want something battery powered like this

If you have a more specific budget and weight and size specs we can help get more specific set up.

Mask is a shrouded bib mask that came in the 25th anniversary costume and this is the voice amplifier WinBridge WB001 Portable Voice Amplifier with Headset Microphone Personal Speaker Mic Rechargeable Ultralight for Teachers, Elderly, Tour Guides, Coaches, Presentations, Teacher https://www.amazon.com/dp/B014JJG43E/ref=cm_sw_r_cp_api_glc_i_M7CHPWZD8ZGSTPSRGPKH?_encoding=UTF8&psc=1

Amazon WinBridge WB001 Portable Voice Amplifier with Headset Microphone Personal Speaker Mic Rechargeable Ultralight for Teachers, Elderly, Tour Guides, Coaches, Presentations, Teacher https://www.amazon.com/dp/B014JJG43E/ref=cm_sw_r_cp_api_glc_i_M7CHPWZD8ZGSTPSRGPKH?_encoding=UTF8&psc=1