Thanks @gfmendes. I don't know why certain words would work better. The TRIGGERcmd Smart Home Alexa skill simulates a light switch for each command, so I thought ligar and desligar would work best. Google Translate tells me those are the translations for "turn on" and "turn off" which is how I tend say it in English. I can also say, "calculator off".
This page gives some background too if you're interested:
https://www.amazon.com.br/gp/help/customer/display.html/ref=hp_bc_nav?ie=UTF8&nodeId=201749260