An animated tutorial explaining the four suffixing conventions we follow when adding -ed. 1.        If the word ends with a CVC pattern and a short vowel sound, we double the final consonant letter before adding -ed. We do not double the consonants w, x, or y – even if the word looks like CVC.  2.        When a word ends in a silent e vowel letter, drop it before adding suffix -ed. 3.        If a word ends in the letter y after a consonant letter, change that y to i, then add suffix -ed. 4.        If the word doesn’t end in a silent e vowel letter, doesn’t end in a letter y after a consonant letter, and doesn’t follow the CVC pattern with a short vowel sound, just add suffix -ed....