The document discusses countable and uncountable nouns in English. It provides examples of nouns that are countable like "sandwich", "egg", "tomato", and "grape", as well as uncountable nouns like "sugar", "lemonade", "rice", and "water". It notes that nouns can become countable when referring to a specific quantity or container, such as a "glass of water", "bar of chocolate", or "slice of bread".