We didn't use a kit. At around 6 months I started using the sign and word when I asked L a question. She now knows: milk, diaper, eat, more, water, dog, bird, yes, no, baby, and kitty.
She is also able to say the words verbally as well but that's only been the last couple months.
"Don't compromise yourself. You are all you've got."-Janis Joplin