Why it matters what pronouns you use to refer to people and what to do if you slip up

(CNN)If you feel like you've been hearing about pronouns a lot lately, you're on to something.

Sam Smith took to Instagram in September to announce that their pronouns are they/them. Merriam-Webster announced a few days later that "they" can also be used to refer to a single person whose gender identity is non-binary, meaning neither male or female. And recently, Sen. Kamala Harris introduced herself at a CNN LGBTQ Town Hall by stating that her pronouns are "she, her and hers."
Maybe all this is new to you. Maybe you're a little confused. Maybe you've been doing this for a while, but you know a friend, coworker or family member who could use some help. Whatever the case, we've got you covered.
CNN talked to Shige Sakurai, the founder of International Pronouns Day and the associate director of the LGBT Equity Center at the University of Maryland, College Park, about why it matters what pronouns you use to refer to people and what to do if you slip up.

What do we mean by pronouns exactly?

Time for a quick grammar refresher.
Personal pronouns are the words used in place of specific people, places or things. Pronouns like "me, myself and I" are how people talk about themselves, and pronouns like "you, she, he and they" are some pronouns that people use to talk about others.
A person's pronouns are the third-person singular pronouns that they would like others to use for them. Personal pronouns are used to convey a person's gender identity and don't necessarily align with the sex a person was assigned at birth.
The most common third-person singular pronouns are "she/her/hers" and "he/him/his." "They/them" can also be used to refer to a single person, while some people use gender-neutral or gender-inclusive pronouns like "ze/hir" (pronounced zee/here) instead. Some people might not use pronouns at all and go only by a name.

Why does it matter what pronouns you use to refer to someone?

Using the pronouns that a person goes by is a way of respecting that person's gender identity -- or a person's emotional and psychological sense of their own gender.
If someone tells you that they go by the pronouns "they/them," for example, and you continue to refer to them using "he/him/his" pronouns, it can imply that you believe that transgender, non-binary or intersex people are unimportant, or shouldn't exist.
Intentionally calling someone by the wrong pronoun can make them feel disrespected or alienated, and can take a toll on their mental health. It is also offensive and can be considered harassment.
Sometimes people can use the wrong pronoun for others without realizing it or meaning any harm. People who aren't used to thinking about what pronouns others use to refer to themselves might make assumptions about someone else's pronouns based on their name or appearance.
But those assumptions can be incorrect and similarly hurtful because they imply a person has to look a certain way to demonstrate their gender identity.

Isn't using 'they/them' to refer to one person grammatically incorrect?

You might have learned in English class that "they" and "them" describe a group of people, while "he" and "she" describe a single person.
But language is constantly evolving, and you need look no further than the foremost authorities on language: dictionaries.
Merriam-Webster recently added a new definition in its entry for "they," noting that the pronoun is also used to refer to an individual whose gender identity is non-binary.
Using "they" to refer to one person isn't just a new thing or a case of political correctness. Sakurai, who uses "they/them" pronouns, says they have been in spaces where this has been a practice for decades.
"It might be something that people are now becoming more aware of in more mainstream, broader spaces, but it's not something that's a new conversation for trans people or even for some people in the LGBT community sometimes," Sakurai said.
In fact, people have been using "they" as a singular pronoun as far back as the 14th century.