The Rule
We double the final consonant of a word before adding "-ed" if these conditions are met:
1. Short vowel sound: The word has a short vowel sound before the final consonant.
2. Single consonant: The final consonant is single (not a double letter like "ll" or "ss").
3. Stressed syllable: The stress falls on the final syllable.
Examples
* "Shop" becomes "shopped": The vowel sound in "shop" is short, the final consonant is "p," and the stress is on the final syllable.
* "Swim" becomes "swam": The vowel sound in "swim" is short, the final consonant is "m," and the stress is on the final syllable.
* "Hug" becomes "hugged": The vowel sound in "hug" is short, the final consonant is "g," and the stress is on the final syllable.
Exceptions
* Words ending in "w" or "y": We don't double the final "w" or "y" (e.g., "snowed," "played").
* Words with more than one syllable and stress on the first syllable: We don't double the final consonant (e.g., "opened," "painted").
* Words ending in "c" followed by a vowel: We don't double the "c" (e.g., "panic-ed," "mimic-ed").
Why This Rule Exists
This rule has its roots in Old English and aims to preserve the short vowel sound when adding the "-ed" suffix. Doubling the final consonant helps to maintain the pronunciation of the word.
Let me know if you'd like more examples or have any other questions about this rule!