Zoe's playing, accompanying her activities with the requisite gibberish shrieks

"You're very loud, Zoe," I say.

"I'm a baby, Daddy," Kate replies in 'Zoe-voice."

"You're a Testerman baby, baby," I reply.

I'm starting to suspect, given all the evidence, that when it comes to 'loud', it's the 'Testerman' part to blame, more than the 'baby' part.