Foundations

Reed-Kellogg Diagrams

A Reed-Kellogg diagram has no labels. Every grammatical fact is carried by where a word sits and what kind of line holds it. Learn the handful of marks on this page and you can read any diagram in this section.

What you’ll learn

Read the base line and know what each kind of vertical divider means
Tell a modifier from an argument at a glance
Recognise the diagonal-and-horizontal shape of a prepositional phrase
Know what a pedestal, a chevron and a dashed line each signal

Position is the label

Most ways of describing grammar attach names to words. Reed-Kellogg does the opposite: it moves the word to a place that means something. A word on the base line is a core part of the clause; a word on a slant below it is a modifier; a word on a raised platform is doing a job the base line has no room for.

The pay-off is that you can see the shape of a sentence before you have read it. The cost is that you must learn the marks, which is what this page is for.

The base line and its dividers

Everything starts with one horizontal line carrying the core of the clause. Vertical lines cut it into slots, and how far a vertical extends tells you what kind of boundary it is. This is the single most useful thing on the page.

A full vertical crosses the base line
It runs above and below. It separates the subject from the predicate, and there is exactly one per clause.
A half vertical stops at the base line
It sits on top and goes no lower. It separates a verb from its direct object.
A backslash leans back toward the verb
A short line slanting up-left. It introduces a complement — a word renaming or describing the subject rather than receiving the action.

“My cousin repaired the fence.”

Reed-Kellogg — full vertical, then half vertical

possPossession modifier
nsubjNominal subject
ROOTRoot of the sentence
detDeterminer
dobjDirect object

Dependency — the same facts, written as labels

Comparing the two views

The Reed-Kellogg diagram encodes “fence is the direct object” in the height of the line before it — a half vertical rather than a full one. Nothing is written down. The dependency parse writes it down instead, as the label dobj, and encodes nothing in position. Each view is silent about what the other states.

Slants: everything optional hangs below

A modifier never sits on the base line. It hangs beneath the word it modifies on a line slanting down to the right, and the slant can chain: a word modifying a modifier hangs off that line in turn.

This is why a Reed-Kellogg diagram grows downward rather than sideways. The base line stays short — it only ever holds the skeleton — while the detail accumulates below it.

“The soup smells wonderful.”

Reed-Kellogg — a backslash carries the complement

detDeterminer
nsubjNominal subject
ROOTRoot of the sentence
acompAdjectival complement

Dependency — acomp, not amod

Comparing the two views

wonderful is not a modifier of soup, even though it describes it — it arrives through the verb. Reed-Kellogg shows that with a backslash on the base line rather than a slant below it, so the picture distinguishes “describes the subject directly” from “describes it via a linking verb”. The dependency parse marks the same distinction with acomp rather than amod.

Diagonals: prepositional phrases

A preposition gets its own two-part shape: a diagonal carrying the preposition, dropping into a horizontal carrying its object. Anything modifying that object hangs on a slant below the horizontal, exactly as it would on the base line.

The shape is recursive — a prepositional phrase can hang off the object of another one, giving the stepped look you see in longer sentences. Full detail is in Prepositional Phrases.

“Nina waited beside the old gate.”

Reed-Kellogg — one connected shape for the whole phrase

nsubjNominal subject
ROOTRoot of the sentence
prepPrepositional modifier
detDeterminer
amodAdjectival modifier
pobjObject of preposition

Dependency — four arcs, and no statement that they form a unit

Comparing the two views

This is where the two views diverge most usefully. Reed-Kellogg draws beside the old gate as one connected shape hanging under the verb, so its boundaries are visible: you can point at where the phrase starts and stops. The dependency tree has no notion of a phrase at all — it gives you three separate arcs (prep, det, amod, pobj) and leaves the grouping for you to work out. If you want to know which words form a unit, read the Reed-Kellogg. If you want to know exactly how each word attaches, read the tree.

The remaining marks

Four more shapes cover almost everything else you will meet. Each has its own topic page; this is the map.

Pedestal (a stand): A small triangle or stem lifting something above the base line. It means “this whole construction is filling a single slot” — a gerund phrase acting as a subject, or a clause acting as an object. Swimming keeps her fit. — the gerund stands on a pedestal in the subject slot. She knows that we left. — the whole clause stands on one in the object slot.
See: Gerunds, Infinitives, Noun Clauses
Chevron (a fork): The base line splits into two or more parallel branches that rejoin. It means coordination: two subjects, two verbs or two objects sharing everything else. The conjunction sits on a dashed line between the branches. Jack and Jill fell. — two subjects fork before one verb. She washed and dried the plates. — one subject, two verbs.
See: Imperatives & Conjunctions, Compound-Complex Sentences
Dashed line: A connection that is grammatical rather than structural — it joins two things without either being part of the other. Subordinating conjunctions, relative pronouns and coordinating conjunctions all travel on dashed lines. We left because it rained. — because runs on a dashed line down to its clause. The book that you lent me is here. — that is joined to book the same way.
See: Adverb Clauses, Adjective Clauses
A line with no connection: A short horizontal floating above the diagram, attached to nothing. It marks an element standing outside the clause’s grammar altogether: a person being addressed, or an adverb commenting on the whole sentence. Children, we must hurry. — Children floats above the clause. Frankly, the plan failed. — so does frankly.
See: Adverbs, Possessives & Appositives

Practice on a real sentence

Drag across a span of words and name the role it plays. Each correct answer draws one more piece of the diagram, so you are building the picture rather than reading a finished one. This sentence has a chevron in it — two verbs sharing one subject.

“Barbara mowed and watered the lawn.”

Grammatical roles

Drag across a span and name the role it plays. Builds both diagrams.

Words 6Roles 0/6Attempts 0Correct 0Time 0:00

Sentence — select a role below, then drag across word(s) here

Barbara mowed and watered the lawn.

Constituent boxes

Confirmed spans appear here as colored borders

Reed-Kellogg diagram

The Reed-Kellogg diagram is built here as each role is confirmed