Why is it spelled "maintenance" and not "maintainance?"?

Question

Why is the task of maintaining spelled "maintenance" and not "maintainance?" Other words related to maintaining include: maintain, maintained, maintainer, maintainability, and maintainable. Each of those words starts with ***maintai-***, so it would logically make sense to write **maintainance** instead of **maintenance** because it would have the same "ai" instead of "e".

Answer 1

The task of maintaining is spelled "maintenance" and not "maintainance" based on pronunciation. The word is spoken as "main-TEN-ence" and not "main-TAIN-ence" and thus the word is spelled as "maintenance."

It is a grammatical nuance of the English language that, unfortunately, will not be going away.