That and who are both subject and/or object pronouns. Who is used only when referring to people (yeah, I think animals are people, too) while that can be used for people, things, and animals.
I have a strong personal preference toward using who in any situation that involves people or animals while reserving that for things—or people or animals for whom I have no respect.
It’s a personal choice between being respectful (in my opinion) and being easy.
|Refers to People|
|Part of Grammar: Relative pronouns introduce relative adjectival clauses.|
|Who||Subject or object pronoun for people||I told you about the woman who lives next door.|
|Whose||Possessive for people, animals, and things||Do you know the boy whose mother is a nurse?|
|Whom||Object pronoun for people
|I was invited by the professor whom I met at the conference.|
|Refers to Things|
|That||Subject or object pronoun for people, animals, and things in defining relative clauses which could also use
|I don’t like the table that stands in the kitchen.
Technically, you can also say:
|Which||Subject or object pronoun for animals and things.
It can also refer to a whole sentence.
|Do you see the cat which is lying on the roof?
He couldn’t read which surprised me.
C’mon, get it out of your system, bitch, whine, moan…which words are your pet peeves?
Kathy Davie is an author, educator, and artist with a BS in Technical Writing & Editing with minors in Digital Media and History from Metropolitan State College in Denver, Colorado
She is the author of the arts marketing series, Your Portfolio & You, aimed at helping artists survive (and thrive) at the business of being an artist and include Accounting for the SMALL Businessperson, How Copyright Applies to the Artist, the Buyer, the Employer/e, the Sold Artwork, Dealing with Photographs, Slides, Digital Images, and Surviving the Outdoor Arts Festival.
A huge believer in knowledge being power, Kathy has begun a free set of Author Tools for authors interested in self-editing including an online tutorial in Using Microsoft Word’s Markup Tool, words commonly confused by authors and Punctuation and Formatting Tips.