Getting user to say only the missing word from a phrase

1. What is it called when you miss words out of a sentence?
2. How do you write a missing word in a sentence?
3. What is it called when you skip words when writing?

What is it called when you miss words out of a sentence?

Ellipsis happens when we leave out (in other words, when we don't use) items which we would normally expect to use in a sentence if we followed the grammatical rules.

How do you write a missing word in a sentence?

It's the carat ^, a proofreading symbol that indicates where something should be inserted. A caret shows where an additional or corrected or substituted letter, word, or phrase is to be inserted in or above the line.

What is it called when you skip words when writing?

You can use an ellipsis—three consecutive periods, with one space around each ( . . . )—to leave out extra or unnecessary words.