Suffix -TY is a consonant suffix and changes a word to name a “condition” or “quality”, as in “royal” to “royalty”.

Suffix /tē/, Suffix /tē/, Suffix /tē/, royalty

Sometimes T-Y at the end of the word is not Suffix -TY. For example, “dusty” uses Suffix -Y instead because the base word is “dust”. The T is already part of the base word and Suffix -Y is added. “Dusty” does not use Suffix -TY because the word is not “dus” plus Suffix -TY; rather, it is “dust” plus Suffix -Y.