Preposition stranding

Many English learners hear a rule early: Never end a sentence with a preposition. Then they hear native speakers do it all day:

“Who are you talking to?”
“That’s the topic I’m interested in.”
“This is the chair I sat on.”

This is not sloppy English. It is a normal structure with a name: preposition stranding. Modern grammar descriptions treat it as standard in many contexts, and they explain when it sounds natural and when it sounds forced.

What a preposition is

A preposition links a noun phrase (or pronoun) to another part of the sentence. In simple cases, it sits in front of its object:

“She sat on the chair.”
“We talked about the plan.”
“This gift is for you.”

In those examples, on / about / for each has an object right after it: the chair / the plan / you.

Preposition stranding happens when that object moves away, but the preposition stays behind.

The basic idea of “stranding”

Think of a preposition as wanting a partner (its object). English sometimes moves that object to the front of a clause—for a question, for emphasis, or to build a relative clause. When the object moves, the preposition can be left at the end (or near the end). That “left behind” preposition is stranded.

Two common structures create stranding:

Questions
Relative clauses (“the person that…”, “the place I…”)

A third, less obvious one is:

Prepositional passives (“This bed has been slept in.”)

Let’s take them one by one.

1) Stranding in questions

Start with a basic statement:

“You are talking to Maria.”

Now turn it into a question. English often moves a question word to the front:

“Who are you talking to?”

Here, who is the object of to, but it appears at the start. The preposition stays at the end. That is stranding.

Many learners try to “fix” this by pulling the preposition forward:

“To whom are you talking?”

That version is grammatical, but it is formal and can sound stiff in daily speech. In most conversation, stranding is the default.

A useful pair to learn: stranded vs fronted

These pairs mean the same thing but fit different situations:

Informal: “Who did you go with?”
Formal: “With whom did you go?”
Informal: “What are you looking at?”
Formal: “At what are you looking?”
Informal: “Which company do you work for?”
Formal: “For which company do you work?”

A simple guideline for learners: In speech, strand. In formal writing, choose based on tone. Stranding is not “wrong”; it is a choice.

2) Stranding in relative clauses

Relative clauses describe a noun:

“That’s the person who called.”
“This is the book that I bought.”

Relative clauses are also where English strands prepositions all the time:

“This is the topic (that) I’m interested in.”
“That’s the colleague (who/that) I was talking to.”
“Here’s the form (that) you need to apply for.”

Notice something important: English can even drop the relative pronoun:

“That’s the colleague I was talking to.”
“Here’s the form you need to apply for.”

This is one reason stranding is so common: it lets English build short, smooth noun phrases.

The “pied-piping” alternative

The formal alternative pulls the preposition to the front of the relative clause:

“This is the topic in which I’m interested.”
“That’s the colleague to whom I was talking.”
“Here’s the form for which you need to apply.”

This structure is called pied-piping in linguistics (the preposition “drags” its object along). You do not need that term to use the pattern, but it helps to know there are two options.

A practical point: in which / for which / to whom are common in academic prose, reports, and legal writing. In everyday writing, they can sound heavy.

3) Stranding in prepositional passives

English can turn some “preposition + object” relationships into passives:

Active: “Someone has slept in this bed.”
Passive: “This bed has been slept in.”
Active: “People talk about her a lot.”
Passive: “She is talked about a lot.”

Learners often avoid these because they look strange. But they are natural in English, especially when the object is the thing we want to talk about first (the bed, the person, the topic).

Why the “no preposition at the end” rule exists

The “rule” is a prescriptive rule: advice about how people should write, not a description of how English works. Many writers and editors repeated it for centuries, so it became a classroom slogan.

A common account traces early criticism of stranded prepositions to the 1600s and later style traditions, with strong influence from Latin-based ideas of “good” grammar.

The key point for learners is simpler than the history: English has allowed stranding for a long time, and major modern references accept it in many contexts.

The famous Churchill line (and what it teaches)

You may have seen the joke:

“This is the sort of nonsense up with which I will not put.”

It is used to mock the anti-stranding rule by showing what happens when you force every preposition to the front: the sentence becomes awkward.

Whether Churchill said it is uncertain; many sources treat the attribution as doubtful or at least disputed.

Even if you forget the quote, remember the lesson: a “rule” that makes sentences worse is a bad rule to follow without thinking.

What learners should do in real English

Here is the teaching problem: learners want one rule they can apply fast. English gives you a choice instead. So use a decision process.

Step 1: Choose the tone

Conversation, email, chat: stranding is usually best.
Formal letter, academic paper, legal text: consider fronting the preposition.

Step 2: Avoid the worst kind of “formal”

Fronting can help, but it can also sound like a trick. These are often poor choices:

Awkward: “To whom did you give it?” (in casual speech)
Awkward: “At what are you looking?” (almost nobody says this)

If you need a formal tone, pick a structure that fits formal English:

Better: “Whom did you give it to?” (formal but still close to speech)
Better: “What are you looking at?” (plain and clear)
Better formal rewrite: “What are you looking at?” → “What are you examining?”

Formal writing often avoids the issue by choosing a different verb:

“deal with” → “address”
“look at” → “examine”
“talk about” → “discuss”

This is not “cheating.” It is normal editing.

Step 3: Learn the high-frequency patterns

If you master these, you will sound natural fast:

Questions

“Who are you waiting for?”
“What does it depend on?”
“Which drawer did you put it in?”

Relative clauses

“That’s the person I told you about.”
“This is the project she’s working on.”
“Here’s the tool I was looking for.”

Short answers
English often strands in answers too:

“What are you thinking about?” — “I don’t know what I’m thinking about.”

Step 4: Don’t strand when it creates confusion

Stranding can sometimes leave the reader hunting for the connection. For example:

“The policy we spoke yesterday about…” (clumsy order)
Better: “The policy we spoke about yesterday…”

The issue here is not stranding; it is word order. Put time words where they belong.

Step 5: Know the fixed formal set

In careful writing, some fronted forms are common and useful:

in which, for which, by which, with which
to whom, of whom

Example:

“The method by which the data were collected is described in Appendix A.”

This is the register where pied-piping feels normal.

What preposition stranding is not

Two quick clarifications help learners avoid wrong “fixes.”

It is not a mistake caused by laziness.
It is part of English sentence building, especially in questions and relatives.
It is not the same as a random preposition at the end.
In true stranding, the preposition has an understood object earlier in the clause:

“Which chair did you sit on?” (object = which chair)
“This is the chair I sat on.” (object = the chair)

If you end with a preposition that has no object at all, then you may have a different problem:

“I put it on.” (Here on is part of a phrasal verb-like pattern; the object is “it,” and the sentence is complete.)
English has several patterns that look similar on the surface. Stranding is only one of them.

A short summary you can trust

Preposition stranding is normal in English, especially in questions and relative clauses.
Fronting the preposition is also possible and tends to sound formal.
The old “never end with a preposition” rule is a style tradition, not a law of English grammar.
Good writing chooses the form that keeps meaning clear and tone right.