They will learn irregular forms later as they build up experience. Not all languages have singular and plural forms for nouns. In Maori, and in spoken French, a plural is indicated by a change in the definite article rather than in the noun itself. The French words chien and chiens are pronounced the same, even though they are spelled differently. Chinese students learning English often have difficulty with the plural -s form because in Chinese the plural is not indicated in the word form.
Some nouns refer to one particular person or place.
These are called proper nouns , and they always have a capital letter. Most proper nouns do not have the in front of them. Nouns that are not proper nouns are called common nouns . These are called concrete nouns . These are called abstract nouns .