Elderspeak

Elderspeak (infantilization or secondary baby talk) features simplistic vocabulary and grammar, shortened sentences, slowed speech, elevated pitch and volume, and inappropriately intimate terms of endearment. 

Excerpted from: 
Williams KN. (2008). Elderspeak Communication: Impact on Dementia Care.
Am J Alzheimers Dis Other Demen. 2008 Jun 30.