What is the term used to describe verbs that change their spelling when written in past tense?

Verbs that change their spelling when written in past tense are called irregular verbs.

These verbs don't follow the standard rules of adding "-ed" or "-d" to form the past tense. They have unique, often unpredictable, changes in their spelling.

Here are some examples of irregular verbs:

* Go -> Went

* See -> Saw

* Eat -> Ate

* Run -> Ran

* Sing -> Sang

Learning to recognize and use irregular verbs correctly is essential for proper English grammar.