Final answer:
It is true that Jonathan and Mina use shorthand to communicate in private, as depicted in Bram Stoker's novel Dracula, to keep sensitive information about Dracula secure.
Step-by-step explanation:
The statement that Jonathan and Mina use shorthand to communicate in private is True. This occurs in Bram Stoker's gothic novel Dracula, where Mina Murray is proficient in shorthand, which is a method of rapid writing by means of abbreviations and symbols. This skill proves quite useful as she and Jonathan Harker, her fiancé, employ this technique to keep their journal entries and letters private, especially when they contain sensitive information about their experiences with the vampire Dracula.