Nobody else is going to be able to answer your questions to your satisfaction.
Everyone experiences this stuff differently.

I experience random dialogue-like thoughts all the time, and it's not related to my DID. It's just my brain firing stuff off like it's offloading electricity. Obsessing/focusing on it is part of OCD/anxiety. You should talk to your doctors about it.

Edit to add:
Internal dialogue is also not a DID-specific thing. Many people without DID experience internal dialogue.