Dogs understand not just the tone, but also the meaning of words.
"Dogs process both what we say and how we say it in a way which is amazingly similar to how human brains do."
This is a key theme in the Singularity's Children series - forget aliens for the time being (its OK, calm down, they are coming!) we are already not alone - animals are much smarter than we give them credit for.
http://www.npr.org/sections/health-shots/2016/08/30/491935800/their-masters-voices-dogs-understand-tone-and-meaning-of-words
"Dogs process both what we say and how we say it in a way which is amazingly similar to how human brains do."
This is a key theme in the Singularity's Children series - forget aliens for the time being (its OK, calm down, they are coming!) we are already not alone - animals are much smarter than we give them credit for.