Here's another Thai-English gap worth slowing down for. In Thai, a noun doesn't change at all whether you mean one or many — 'หนังสือ' means both 'book' and 'books'; the number is understood from context or a classifier word. In English, countable nouns must add '-s' (or '-es') when there's more than one, and this is one of the endings Thai learners drop most often, especially in speech.

Most nouns just add -s: book -> books, dog -> dogs. Nouns ending in -s, -x, -ch, -sh add -es: box -> boxes, watch -> watches. Nouns ending in a consonant + y change y to i and add -es: city -> cities. And a small set of very common nouns are irregular and must be memorized: child -> children, man -> men, woman -> women, person -> people. 🔊