Final answer:
In English, to form plurals of nouns ending with -y, we change the -y to -i and add -es if the -y is preceded by a consonant. If the -y is preceded by a vowel, we simply add -s.
Step-by-step explanation:
Rule 3, commonly known as the "Y-Ending Plurals" rule, provides a clear guideline for forming plurals when a noun ends with the letter -y. This rule distinguishes between cases where the -y is preceded by a consonant and when it is preceded by a vowel.
In instances where the -y is preceded by a consonant, the rule directs us to change the -y to -i and add -es. A classic example is the noun 'baby,' where the plural form is 'babies.' Here, the consonant 'b' precedes the -y, adhering to the rule, and resulting in the alteration of the -y to -i followed by the addition of -es.
Conversely, if the -y is preceded by a vowel, the rule specifies a simpler procedure: add -s to form the plural. Take the noun 'day' as an illustration, where the -y is preceded by the vowel 'a.' Following the rule, we merely append -s to the existing form, yielding the plural 'days.'
This rule streamlines the pluralization process for words ending in -y, offering learners a systematic approach. By distinguishing between consonant and vowel precedents, it provides clarity and consistency in forming plurals, contributing to grammatical accuracy in written and spoken English. Understanding and applying such rules enhance language proficiency and aid effective communication.