This. Is. Brilliant. The Panasonic KX-TGM420 Series amplified cordless system features a voice volume up to 40 decibels (dB) to make caller voices easier to hear, and so you don't miss a call, and the base unit can be set to ring loudly at up to 112 dB. Bright red LED visual ringers on the base unit and handset flash when there is an incoming call, and the phone is also compatible with hearing aids.
But the most exciting feature has to be "Slow Talk" -- which slows the speed of speech in real time and when checking voice messages.