What would not require a spelling change before attaching the portable part -er to end?

Here's a breakdown of what *doesn't* require a spelling change when adding "-er" to form a noun:

Words ending in "e":

* Example: "write" becomes "writer" (no spelling change)

* Why: The "-e" is dropped before adding "-er"

Words ending in a consonant followed by "y":

* Example: "carry" becomes "carrier" (no spelling change)

* Why: The "y" changes to "i" before adding "-er"

Words ending in "le":

* Example: "noble" becomes "nobler" (no spelling change)

* Why: The "-le" remains the same.

Words ending in "-er" already:

* Example: "baker" (already has the "-er" suffix)

* Why: Adding another "-er" would create a double "-er" (e.g., bakerer), which is incorrect.

Important Note:

* While these rules are generally true, there are always exceptions in English. For example, "use" becomes "user" (not "user").

Let me know if you'd like more examples or have any other questions!