I’m pretty fluent when talking to myself and even more when I speak to my dog. I’ve found breathing exercises and calming myself helps a lot. I’m even more fluent when I’m angry and yell. I have a lot of built up frustration and anxiety from being bullied and getting the short end of the stick in life. You may not be comfortable with yourself or the animal(s) you are speaking to. I’m guessing they are not yours? Are they’re other people around when you speak to these animals? Because you may be subconsciously having anxiety or or angst that you may be still judged, if there are other persons around.