Shorthand is full of these. Every shorthand writing system has the omission of constants, words, vowels, etc.
You will find this in longhand writing also. When taking notes for a class, lecture, sermon, meeting, etc., you will find that you abbreviate and take out the nonessential. For example, when you write 'memo' instead of 'memorandum', you may also write 'mtg' for 'meeting', 'recd' for 'received', etc.
You also do this in internet boards and text messaging. 'Lol' for 'laughing out loud', etc.
If an omission would lead to hestiation in reading, the full form must be written.
Students must learn the coniditons of the omissions.
Remember that the omission of vowels gives a certain clue to the word representated, as all other vowels would be inserted.
Some people don't have to sign their name in full, such as John Henry Brown may sign John Brown or J. H. Brown or John to save time. Also, J. K. Rowling. Hers may have started to get boys to read a novel written by a woman, but it's what she's known by now.
When reading the word back, the name is recognized by the form, just as a banker recognizes the writer of a check by his signature.