Why English and Spanish form their plurals using an S

Languages that form noun plurals by adding an “s” include just a handful and are some of the most widely spoken languages in the world.

1. English:
   • Most nouns form their plural by adding “s” (e.g., cat → cats, car → cars).
   • If the noun ends in -s, -x, -z, -sh, or -ch, an “es” is added (e.g., bus → buses, box → boxes)​
2. Spanish:
   • Similar to English, most nouns add “s” (e.g., casa → casas, libro → libros).
   • If a noun ends in a consonant, “es” is added (e.g., árbol → árboles, mujer → mujeres)​ 
3. Portuguese:
   • Regular nouns generally add “s” (e.g., casa → casas, carro → carros).
   • Nouns ending in -r, -z, or -s add “es” (e.g., flor → flores, rapaz → rapazes)​ 
4. French (S for plural is mute most of the time):
   • Most nouns add “s” (e.g., chat → chats, livre → livres).
   • However, final consonants are often not pronounced, its mute, making the singular and plural forms sound the same.

The formation of plurals with an “s” in English, Spanish, French, Portuguese, Catalan, and Galician (north of Spain), and probably that’s about it, mainly stems from historical linguistic developments. Here are some key reasons:

1. Latin Influence: Many Romance languages (like Spanish, French, Portuguese, and Italian) evolved from Latin. In Latin, plurals of many nouns in the second declension ended in “-i” for masculine nouns and “-ae” for feminine nouns, but in the third declension, plurals often ended in “-es.” Over time, the “-es” ending became simplified to just “s” in the vernacular languages.
2. Germanic Influence: In Old English, which has Germanic roots, plurals were formed in various ways, including adding “-as.” This influenced the development of Middle English, which eventually simplified many plural forms to just “s.”
3. Ease of Pronunciation and Consistency: Adding an “s” to form plurals is a simple and consistent rule, which likely contributed to its adoption and persistence. It provides an easy way to distinguish between singular and plural forms in speech and writing.
4. Norman Conquest: The Norman Conquest of England in 1066 brought a significant French influence to the English language. French pluralization rules, which predominantly used “s,” were adopted into English during this period.
5. Language Standardization: As languages evolved and became standardized, the more regular and simpler pluralization rule of adding “s” became more dominant. This standardization helped in creating uniformity in written and spoken language, making it easier for speakers and learners.

Overall, the use of “s” for plurals is a result of historical linguistic evolution, influenced by Latin and Germanic roots, as well as the practical benefits of a simple and consistent grammatical rule.

For more information:

• McWhorter, John H. “The Power of Babel: A Natural History of Language.” Harper Perennial, 2003.
• Trudgill, Peter. “Sociolinguistics: An Introduction to Language and Society.” Penguin Books, 2000.

Now, if you took the plural-S for granted, here is a list of languages that do NOT form their plurals using an S:

Languages that do not form their plurals by adding an “s” include Italian, German, Russian, Japanese, Chinese (Mandarin), Arabic, Hebrew, Turkish, Finnish, Hungarian, Greek, Polish, Czech, Slovak, Lithuanian, Latvian, Estonian, Korean, Thai, Vietnamese, Hindi, Bengali, Tamil, Telugu, Malayalam, Kannada, Marathi, Punjabi, Urdu, Persian, Pashto, Swahili, Amharic, Somali, Georgian, Armenian, Basque, Icelandic, Welsh, etc. These languages use a variety of methods such as vowel changes, suffix additions, internal modifications, and context to indicate plural forms.