I usually say appreciate it or preciate your help or something like that. When I answered the phone when I was younger I would struggle with Hello or Hi - now I just say Yo or some other casual greeting if I know the person well instead of a hello Some people say substitutions are bad and a form of hiding your stutter, but I really enjoy finding creative ways to say things. I have a great vocabulary because of it. I challenged myself to become a master of the English language in high school and I think I'm pretty close in my 30s. I don't really think about it but I know it's something I just do subconsciously.