Speech I think is a big developmental stage so yes it probably is impacting.
30mins is on the long side, although there are times I'v done longer with both my children & my almost 19mo is definitely needing at least 20mins worth of stories & cuddles from me at the moment... while our 3yo would have had more at the same age I think as both dh & I did stories.
I actually think it is likely she will need the longer wind-down when the baby comes along, as at 6weeks to go, that may also by playing a part with your daughter, she can probably pick up that things are changing & most people seem to find that their children need that extra time at bedtime when a new baby comes along to "cope" with the changes. One book I once read said that that - the closeness of reading stories & cuddles at bedtime, allows children to "transfer" negative energy to the greater body mass of a parent & relax for sleep, if they don't get to do that, then crying is the way they release negative energy. I certainly hold that as very true with my children.