Namely if you are for example a Halfling using Disguise Self into a Drow, you will get both Halfling and Drow answer options, if they are both available.
Actually sometimes you do, sometimes you dont.
For example when I ask that old woman in the grove for the gruel as a Halfling masking as Drow, I do NOT get the option to get two Gruel.
That I get without disguise (on said Halfling) or disguised as a Halfling.