Under which conditions does the doubling rule apply?

The doubling rule pertains to the spelling of certain words when adding suffixes, particularly when a base word ends in a single vowel followed by a single consonant. The rule states that if this base word has the stress (or accent) on the last syllable, the final consonant is doubled before adding a vowel suffix.

The condition that ensures the doubling rule applies involves having one vowel followed by one consonant, and the presence of an accent on that final syllable. When suffixes that begin with a vowel (such as -ing, -ed) are added, doubling the consonant helps retain the original pronunciation and syllable structure of the word.

In contrast, having two vowels or two consonants changes the scenario significantly. The absence or presence of suffixes also alters whether the doubling rule applies. Therefore, the critical elements for applying the doubling rule accurately lie in having that single vowel and consonant at the end of the word, along with the stress on the final syllable.