One of the best communication tools to have in your arsenal as an IPT parent is sign language. We used Joseph Garcia's kit, pictured here:
One awesome thing about infants is that they can sign much earlier than they can talk. How much earlier? While the kit says infants around 7-9 months will sign, we've experienced it much earlier with our kids. Our son started "mabbling" (manual babbling) around the age of 5 months or so, and our daughter has been since around the time she was 6 weeks. The main thing to remember is that a baby's signs won't be perfect. For example, our daughter's sign for poop is to bring her hands together, and then to pull them apart, very deliberately. That might sound like a vague thing, but as you get to know your baby, you'll be able to tell the difference between mabbling and when she's just playing with her hands. In addition, she will sign"mommy" by deliberately bringing her fist to her chin.
The key to teaching your baby sign language is to do it often, and in context. Don't just sit there saying potty and showing her the sign unless you're about to go to the potty, are on the potty, or just got back from the potty. Otherwise, she will be confused as to what you're talking about. The prime time to teach a sign is when you have good eye contact with your baby. Also, you can gently sign on your baby. For example, if you are teaching her the sign for "poop", you can gently pull her thumb. Or, if you're teaching her "mommy" you can tap her chin gently with the thumb of your open hand.
You'll be amazed at the enhanced communication you'll have with a preverbal or barely verbal baby. Our son, at around 1 year, had just pooped on the toilet. He looked down at what he had done, and then signed "fish." Evidently he thought the poop floating around looked like fish swimming in the water. We thought it was hilarious. Had he not known sign language, we would've missed out on a lot of what was going on in our son's head before he began talking.
Sign language can help you with IPT because it builds on the verbal cues you'll be using. Also, sometimes babies are more at ease when you communicate with signs rather than verbally. I wonder if it's because verbal communication can seem overwhelming sometimes; manual signs are much more unique, whereas many words may sound like poop or potty to a baby.
We found that sign language helped our son so much when he was getting upset about something. If we just asked him to sign what he needed, many times he would calm down and could tell us what he needed. He would even sign pain, point to his mouth, and ask for medicine when he was teething. I can guarantee you, you will not regret teaching your baby to sign.