Who, Which or Whose? Why Children Pick the Wrong Joining Word

19 October 2026 · by Larry

A child writes “I met a girl which lives next door” and the sentence is nearly right. Everything is spelt properly, the tense is fine, the idea is clear. One small joining word is wrong, and in an editing or grammar exercise that is the mark that goes. This piece is about who, which and whose: what each one is for, the slips that come up again and again, and a short check you can do at home.

What the joining word is doing

These three words let a child join two short sentences into one longer one. Take “I met a girl. She lives next door.” The second sentence tells us more about the girl, so it can hang off the first: “I met a girl who lives next door.” The little word stands in for “she” and glues the two halves together.

That is why this shows up in composition as well as in grammar practice. A child who can only write short, separate sentences sounds stiff. A child who can say “the teacher who marked my book” or “the bag which I lost” sounds like someone writing properly. The catch is that the joining word has to be the right one.

The three-way rule

• who is for people. “The nurse who helped us was kind.”
• which is for things. “The bus which we missed was full.”
• whose is for belonging. “I met a boy whose bag was torn.” The bag belongs to the boy.

Most children learn the first two as “who for people, which for things” and that is a good start. The slips below are what happens around it.

Slip 1: which for a person

“The man which sold me the ticket.” “My friend which lives in Tampines.” This is the most common one, and it is usually spoken English leaking into writing. In casual speech people say it all the time and nobody notices. On paper, for a person, the word wanted is who.

A quick test that works on a child: swap the joining word for “he” or “she” and see whether it still makes sense. “My friend she lives in Tampines” is clearly about a person, so the word is who.

Slip 2: who for a thing

It goes the other way less often, but it happens: “the book who I borrowed”. A thing is not a person, so it takes which. The same “he or she” test helps in reverse: you cannot say “the book he I borrowed”.

Animals sit in the middle and are a good question for the teacher, because usage varies. A child should follow what the school’s worksheets mark as correct instead of a rule from a website.

Slip 3: whose written as who’s

This one is a spelling slip dressed as a grammar slip. Who’s with an apostrophe is a short way of writing “who is” or “who has”. Whose with no apostrophe is the belonging word. A child writes “the girl who’s bag was lost” because the sound is identical and an apostrophe usually means belonging in other words, like “Mei’s bag”.

The fix is the same unpacking trick used for it’s and its: say the sentence with “who is”. “The girl who is bag was lost” is nonsense, so the word is whose. The piece on their, there and they’re has more on how the apostrophe rule works across several words.

Slip 4: who instead of whose

“I met a boy who bag was torn.” Here the child has reached for who because the boy is a person, which is a sensible instinct. What gives it away is what comes straight after the joining word. If a noun follows (“bag”, “mother”, “dog”), the sentence is about something that belongs to the person, and the word needed is whose. If a verb follows (“lives”, “helped”, “won”), it is who.

• I met a girl who lives next door. (verb after it)
• I met a girl whose cousin lives next door. (noun after it)

Looking at the very next word is a rule a child can apply in two seconds.

Slip 5: saying the person twice

“The teacher who she marked my book was fair.” The joining word has already done the job of “she”, so “she” has to go. The same happens with things: “the bus which it we missed”. A child who does this has usually joined two sentences by dropping the new word in and forgetting to take the old word out.

Reading the finished sentence aloud catches this one almost every time. It sounds wrong to a child who would never say it out loud on purpose.

Slip 6: the joining word is too far from what it describes

“I sat next to a girl in the canteen who was eating noodles.” It is not wrong in a way that costs a mark in most exercises, but it can read oddly: was the canteen eating noodles? The joining word usually works best right after the person or thing it is about: “I sat next to a girl who was eating noodles in the canteen.” This is a composition habit more than a rule, and it is worth mentioning only after the first five are steady.

What helps

• Ask what comes next. A verb after the joining word points to who or which; a noun points to whose.
• Ask whether the word before it is a person or a thing. One second, and it settles who against which.
• Use the “he or she” test. If “he/she” fits, it is a person.
• Join two of her own sentences. Take two short sentences from last week’s composition and ask her to make them one. It practises the skill in her own words.
• Read the joined sentence aloud and listen for a repeated “she” or “it”.

What does not help

• Correcting every spoken slip at the dinner table. In speech, “the man which…” is common and a child who is told off for talking will talk less. The place to fix it is on paper.
• A rule list with no sentences. “Who for people” is easy to recite and still gets applied to the wrong word.
• Treating it as a spelling problem. If she writes “who’s” for “whose”, she may know both words perfectly well. What is missing is the decision about which one the sentence needs.

A six-sentence check you can do at home

Ask your child to fill each blank with who, which or whose. These are made up for this page.

• The boy ___ sits beside me is called Aiden.
• This is the song ___ we sang at assembly.
• I know a lady ___ cat has three legs.
• Is that the girl ___ won the race?
• The shop ___ sells stationery is closed today.
• She is the teacher ___ class went on the trip.

The answers are: who, which, whose, who, which, whose. Look at which ones went wrong rather than the score. If the misses are all the people sentences, it is the which-for-a-person habit. If both “whose” sentences go wrong, it is the noun-after-it check that needs a few more tries.

Where this fits

Joining words like these sit alongside the other small decisions that cost marks in English: whether the verb matches its subject matters here too, because “the boys who sit” and “the boy who sits” both depend on it. When the real worry is that writing sounds choppy, the piece on composition covers getting started, and joining sentences is one of the easiest ways to make a first draft sound smoother. The free English practice has a Who or Which topic at Primary 5, with a short explanation after every answer. Which level learns this is set by the school and the MOE syllabus (moe.gov.sg), so use your child’s own worksheets for the real wording.

These slips often show up inside passages too: the piece on grammar cloze shows how to find the clue around a blank before choosing who or which.

Another small punctuation habit that decides marks in composition is direct speech; see where the speech marks and commas go.

Another small-word trap, this time about meaning, is in vocabulary in context: one word, two meanings.