Isabella has not showed us any communicative output really. She makes sounds, but they are usually Mmms, and Ahhhs, and the Ah-uhs that, depending on the context, can mean anything random. However, with the occasional change in tone in how she says it, it seems that sometimes she means Ah-uh as a "Yes", and other times Ah-uh means "No".
Here are 2 instances…
Instance #1: After rolling in her crib and crying for about 20 minutes, I realized that she will not go down for her nap, so I went to go get her and asked her “Why didn’t you sleep?” and she said “Ah-uh”, in such a diva-nated tone that tells us “Ah-uh, I don’t want to.”
Instrance #2: We were in the car and it started to smell like something died. So I asked my husband if he farted and he defensively said No. I asked my son if he farted and I got another defensive No. Since I was asking and was 100% sure that it wasn’t me, I asked Isabella if she farted, and she answers, “Ah-uh”… like “Ah-uh, I sure did”.