I haven't read any of the replies but I honestly don't think most can relate to an "inner child". I do and some on here do but I think it's safe to say that most of those traumatized don't.
I knew I had super seperated personailties. They feel different. They think different. They have full and complete different personalities. They switch in my head and I even physically moved places without memory of it many times. I am now formally dignosed with OSDD (a pretty new diagnosis, first learning about it on here and bringing it up to my therapist) and I do say "my youngest part" or "my protector" to describe which alter is in the present because that changes how I think about things, understand and grasp things, act, talk, and so forth it's just helpful to know which alter is present. When my "angry teenager" part is present, I fly off the handle more. When my "protector" is present I am numb and don't seem to take in info as well. When my "youngest part" is present, I really don't take in info well and you have to break it down into smaller, almost child-like, pieces for me. When my "sexual seducer part" is present I tend to sexualize things way more. It helps all involved to know this.
All that said, my therapist always says "you". "So, you feel this", "you think that". He is always circling back around to them all being parts of me and reminding me that intergration is the goal. He never says "you're youngest part..." but rather "you..." if that makes sense.
I do think it could be helpful to work on "inner child" work if you already feel that super seperation. If you don't, I don't think it's helpful to try to create a seperation because that is "what's supposed to happen" or what you're supposed to do. Cause that's not true at all.
My therapist wasn't too keen on working with seperate alters either, but I kept bringing it up and when I speak I advise who is present because it helps me and we eventually moved into talking about it. My therapist always does more training here and there. Continual learning, I think is what he calls it. If it is already something that's an issue for you (such as already being seperated) and you'd like to work on it then I'd ask her if she can do some trainings in it as it would be something you'd like to work on. But, again, if it isn't then don't worry with it. I think "the inner child" is an overused term in my own opinion.