Grammatical gender is a system used in many languages to classify nouns, pronouns, and adjectives as masculine, feminine, or neuter. This classification affects how words agree with each other in a sentence. For example, in languages like Spanish and French, the word for "table" is feminine, while the word for "book" is masculine. In languages with grammatical gender, the gender of a noun can influence verb conjugation and adjective forms. This means that speakers must be aware of the gender of each noun to use the correct forms. Not all languages have grammatical gender; for instance, English primarily uses natural gender based on biological sex.