This is the “Change Suffix Ending” icon. When a word ends with vowel Y and a suffix is added, the Y is often changed to I before adding the suffix. The I will most often make the same sound as the Y it replaced.

This does not work whe ending Y is part of a vowel team or the suffix being added starts with an I.

When the Change Suffix Ending function is used, try markup to help you find the base word when decoding and add the suffix when encoding. In decoding, if there is an I before a suffix, write Y underneath the I and treat the Y as the ending Y in the base word. In encoding, put a slash through the Y and write the letter I above it before adding the suffix.