Introduction:
When we don't know or don't want to specify the gender of a person, the pronoun 'they' is used. It is a gender-neutral pronoun that can be used to refer to a single person or multiple people.

Explanation:
The pronoun 'they' is commonly used as a gender-neutral pronoun when the gender of a person is unknown or when we want to avoid assumptions or stereotypes based on gender. It is a way to be inclusive and respectful of individuals who may not identify strictly as male or female.

Example:
For example, if we are talking about a doctor and we don't know if the doctor is male or female, we can say, "They are a doctor." This avoids making assumptions about the gender of the doctor and is more inclusive.

Usage:
Using 'they' as a singular pronoun can sometimes be confusing, as it is traditionally used for plural subjects. However, it has become increasingly accepted and recognized as a singular gender-neutral pronoun. In recent years, there has been a growing recognition of non-binary individuals who do not identify strictly as male or female. The use of 'they' as a singular pronoun helps to acknowledge and respect their gender identity.

Grammar:
When using 'they' as a singular pronoun, it is important to ensure that the verb and other pronouns agree in number. For example: "They are going to the store" instead of "They is going to the store." Similarly, possessive pronouns like 'their' are used instead of 'his' or 'her'.

Conclusion:
Using 'they' as a gender-neutral pronoun is a way to be inclusive and respectful of individuals whose gender may not fit into traditional binary categories. It is important to use language that is inclusive and does not make assumptions about gender. By using 'they' as a gender-neutral pronoun, we can create a more inclusive and respectful environment for all individuals.