The only way to find out if diner lingo is faster is to try it and see.
First a little lingo: “Noah’s boy with Murphy carrying a wreath, splash of red noise, frog sticks, and an MD, hold the hail!”
Now the order, straight: “Ham with potato and cabbage, tomato soup, French fries, and a Dr. Pepper, no ice.”
You’ll note that the colorful version is longer, so efficiency wasn’t the issue. Or was it?
Diner lingo accomplished two things: for one, it amused the cook and customers as waitresses made up new and obscure variations.
For another, the word pictures suggested by the phrases made it easier for a cook and waitress to remember a complete order without continuously consulting paper documentation.
So perhaps the lingo actually did make things more efficient, even if it added a few extra syllables.