Convert speech and or text to whisper - I Would like to get a plugin or software for it. -- 2

Convert speech and (or) text to whisper - I Would like to get a plugin or software for it. I see that there are even some open source thing for it, but I do not know how to put these thing work together. Also some plugin examples what I saw do not give needed quality. What is said in a whisper must be understandable and have a natural effect. Thanks