Free modifier

A free modifier is a phrase or clause, set off by commas, that adds detail to a sentence and can be taken out, and usually moved, without breaking the sentence or changing what it claims.

Sanchez, still in his coat, read the first page twice. Take the bold phrase out and the sentence still stands: Sanchez read the first page twice. Move it and it still works: Still in his coat, Sanchez read the first page twice, or Sanchez read the first page twice, still in his coat. That is the test. A free modifier is free because the main clause does not depend on it.

The terms free modifier and bound modifier were made popular by Francis Christensen, the American writing teacher who also named the cumulative sentence, in his work on sentence rhetoric in the 1960s.

What a modifier is

A modifier is any word, phrase or clause that describes or limits another part of a sentence. In the old key, old modifies key. In she left before dawn, before dawn modifies left. Every modifier is one of two kinds, free or bound, and the kind decides two things: whether it can move, and whether it gets commas.

Free modifiers vs bound modifiers

A bound modifier identifies. It tells the reader which one, so the sentence cannot do without it.

The key that opens the cellar is missing.

Remove the clause and you get The key is missing, which is a different claim. Bound modifiers sit right next to the word they modify and take no commas.

A free modifier adds. The thing is already identified, and the modifier tells you more about it.

The cellar key, which Maria kept on a string, is missing.

Remove the clause and the claim is unchanged: the cellar key is still missing. The commas are the signal to the reader that this part is extra.

The quick test: take the modifier out. If the sentence still says which thing you mean, the modifier is free, so set it off with commas. If the reader is left asking "which one?", it is bound, so leave the commas out.

What counts as a free modifier

Almost any phrase or clause that can be added to a clause that is already complete. Here is one base clause, She put down the letter, with a different free modifier on the end each time.

• Participial phrase: She put down the letter, frowning at the signature. An -ing or -ed verb form describing she.
• Absolute phrase: She put down the letter, her tea going cold beside it. A noun with its own modifier, describing the whole scene.
• Appositive phrase: She put down the letter, a single page in blue ink. A noun phrase renaming the letter.
• Non-restrictive relative clause: She put down the letter, which had arrived without a stamp. A which clause adding a fact about the letter.
• Adjective phrase: She put down the letter, pale and very quiet. Adjectives describing she.
• Prepositional phrase: She put down the letter, with some care. A phrase saying how.

Adverb clauses (when, because, although) work the same way, most often at the front: When the kettle boiled, she put the letter down.

The three positions: initial, mid-sentence and terminal

Where you put a free modifier is a choice, and each position has its own effect. Here is the same phrase in all three.

Initial: before the subject

Frowning at the signature, Maria put the letter down.

An initial modifier gives the reader the frame before the action: a time, a place, a condition, a gesture. It is where most dangling modifiers happen, because the phrase attaches to whatever subject comes next.

Mid-sentence: between the subject and the verb

Maria, frowning at the signature, put the letter down.

A mid-sentence modifier, also called a medial modifier, holds the reader on the subject while the extra detail is delivered. It reads like a pause in speech. Keep it short, and remember it needs a comma on both sides.

Terminal: after the main clause

Maria put the letter down, frowning at the signature.

A terminal modifier, also called a final modifier, arrives after the reader already has the whole statement. It is the easiest position to read and the one that can carry the most, which is why it does most of the work in long sentences.

Why free modifiers matter in fiction

Free modifiers are the reason a long sentence can stay easy to read. Compare two versions of the same information.

Maria, who was standing at the window in the coat that she had not taken off, read the letter, whose signature was a name that she had not seen in twenty years, twice.

Maria read the letter twice, standing at the window, her coat still on, the signature a name she had not seen in twenty years.

The first buries its main verb and makes the reader hold several open clauses at once. The second completes the main clause in five words, then adds a participial phrase and two absolute phrases, which the reader takes one at a time. That second shape is the cumulative sentence.

Why it works: the reader banks the event first, then gets closer and closer detail, which is roughly the order in which we notice things.

Common mistakes with free modifiers

• Only one comma around a mid-sentence modifier. Maria, frowning at the signature put the letter down leaves the phrase half open. Close it: Maria, frowning at the signature, put the letter down.
• Commas around a bound modifier. Students, who miss the deadline, will fail now says that all students miss the deadline. If the clause is identifying which students, drop the commas.
• A modifier with no one to belong to. Frowning at the signature, the letter slipped from her hand has the letter frowning. The subject after an opening phrase has to be the one doing it: Frowning at the signature, she let the letter slip from her hand.
• The same shape every time. A page where every sentence ends with an -ing phrase sounds like a pattern. Vary the type and the position.

If your sentences keep tangling at the commas, that is the kind of thing a line edit sorts out line by line.

Frequently asked questions

What is a free modifier?

It is a phrase or clause that adds detail to a sentence whose main clause is already complete. It is set off by commas and can be removed without changing what the sentence claims.

What is the difference between a free modifier and a bound modifier?

A bound modifier tells the reader which thing is meant, so the sentence needs it and it takes no commas. A free modifier adds information about something already identified, so it can come out, and it is set off by commas.

Are free modifiers always set off by commas?

Almost always, though dashes or brackets can do the same job when you want a sharper break. The one common exception is a short opening phrase such as 'In 1998' or 'At dawn', which many writers leave without a comma.