"I cannot add anything more."
Translation:No puedo añadir nada más.
That would be "I cannot add something more", and I'm not sure if you can say that. It's "No puedo añadir nada más" because Spanish uses double negatives.
It's more that Spanish treats negation as a property of the whole clause, so you don't count up the negative words. So, you could have a "triple" negative, like this:
No hay ningún perro aquí ladrando a nadie. There is not any dog here barking at anyone.
If you thought about it long enough, you could probably even come up with a quadruple. (Say, extend it to be, "...a nadie, nunca." Which would be, "...at anyone, ever.")
But really, it's just that the whole statement is negative.
I thought so too. I'm replying to your comment so I get notified when someone answers.
Aumentar translates more as "augment" or "increase" or "grow." In English we would never say, "We cannot increase anything more." If you wanted to use aumentar the English sentence would be "We cannot increase it further" (No podemos aumentarlo mas).
Aumentar means "to increase". Doesn't really make sense in this sentence.
"Nada mas" = "nothing more" and "mas nada" = "more nothing". For example, you are driving through a forest and someone asks, "What do you see?" and you reply "more trees" (mas arboles). Then you are driving through the desert and you are asked, "What do you see?" and you reply, "mas nada" (more nothing). However they are not interchangeable in terms of meaning. "Nada Mas" is "not an another thing" and "mas nada" would be the equivalent of saying "more nothingness."
Thanks for the thoughtful comments, everyone. The double-negative thing was bothering me as an English speaker.
If one uses double negatives in the English language he is subject to the presumption that he was inadequately educated. (inadecuadamente educada)
I expect I sound that way anyway, in Spanish, but at least I can now quit worrying about glaring double-negatives.