Foundations

Reed-Kellogg Diagrams

A Reed-Kellogg diagram has no labels. It shows each word’s job by where the word sits and what kind of line holds it. Learn the ten marks on this page, and you can read most of the diagrams in these lessons.

What you’ll learn

Tell the three base-line marks apart: the full vertical, the half vertical and the backslash
Tell a core word on the base line from a modifier on a slant below it
Recognise the diagonal-and-horizontal shape of a prepositional phrase
Say what a pedestal, a chevron, a dashed line and a floating line each mean
Read a whole diagram in order, starting from the full vertical

Position is the label

Most ways of describing grammar attach names to words. Reed-Kellogg does the opposite: it puts each word in a place that means something.

A word on the base line is a core part of the clause: the subject, the verb, a direct object or a complement.
A word on a slant below another word is a modifier of that word.
A phrase or clause on a pedestal, a small stand, fills one slot as a single unit.

The advantage is that you can see how a sentence is built from its shape alone. The cost is that you must learn the marks first, and this page teaches them.

The base line and its dividers

Every diagram starts with one horizontal line, the base line, which holds the core of the clause. Short dividers cut it into slots, and the shape of each divider tells you what kind of boundary it is. This is the 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
Its foot stands on the base line and its top leans back, like the sign \. It introduces a complement: a word that renames or describes the subject instead of receiving the action. After a direct object, the same mark introduces an objective complement, a word that renames or describes the object.

“My cousin repaired the fence.”

Reed-Kellogg — full vertical, then half vertical

poss Possession modifier
nsubj Nominal subject
ROOT Root of the sentence
det Determiner
dobj Direct object

Dependency — the same facts, written as labels

Comparing the two views

Both views agree: cousin is the subject, fence the direct object, and My and the are modifiers. Reed-Kellogg shows this with lines, such as the half vertical before fence; the tree uses labels, such as dobj. Each view also shows something the other cannot. Only Reed-Kellogg shows the predicate as one piece: everything to the right of the full vertical. Only the tree names the kind of modifier: poss (possession modifier) for My and det (determiner) for the. Reed-Kellogg puts both on the same plain slant.

Slants: everything optional hangs below

A modifier never sits on the base line. It hangs on a line slanting down to the right, beneath the word it modifies. Slants can also chain: a word that modifies a modifier hangs from that modifier’s slant, as in surprisingly quickly on the Adverbs page.

This is why a Reed-Kellogg diagram grows downward, not sideways. The base line holds only the core of the clause, and the details collect below it.

Not every describing word is a modifier. In the figure below, wonderful describes the soup, but it completes the verb smells, so it sits on the base line, not on a slant. In the wonderful soup, it would be a modifier and hang under soup. This is also why English says smells wonderful, not smells wonderfully: after a linking verb, the word describes the subject, so it is an adjective.

“The soup smells wonderful.”

Reed-Kellogg — a backslash carries the complement

det Determiner
nsubj Nominal subject
ROOT Root of the sentence
acomp Adjectival complement

Dependency — acomp, not amod

Comparing the two views

Both views treat wonderful as part of the predicate, not as a modifier of soup. Reed-Kellogg puts it after a backslash, which points back to the subject it describes. The tree hangs it from smells as acomp (adjectival complement); a modifier of soup would hang from soup as amod.

Diagonals: prepositional phrases

A prepositional phrase gets a two-part shape: a diagonal carrying the preposition, which drops to a horizontal carrying its object. Words that modify the object hang on slants below the horizontal, as they would on the base line.

Most prepositional phrases are modifiers, so the diagonal hangs from the word the phrase describes. In the figure below it hangs from the verb, because beside the old gate tells where Nina waited. In a book about birds, the phrase tells which book, so about hangs from book.

The shape can repeat: a prepositional phrase can hang from the object of another one, which gives longer sentences a stepped shape. Full detail is in Prepositional Phrases.

“Nina waited beside the old gate.”

Reed-Kellogg — one connected shape for the whole phrase

nsubj Nominal subject
ROOT Root of the sentence
prep Prepositional modifier
det Determiner
amod Adjectival modifier
pobj Object of preposition

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

Comparing the two views

Here the two views differ most. Reed-Kellogg draws beside the old gate as one connected shape under the verb, so you can see where the phrase starts and stops. The tree has no mark for the whole phrase. It has four separate arcs instead: prep, pobj, det and amod. To find the phrase in the tree, take beside and every word that hangs below it. Read Reed-Kellogg to see which words form a unit; read the tree to see exactly how each word attaches.

Reading a whole diagram, step by step

Read a diagram from the base line outward, not word by word. Here is the order, applied to the figure just above: Nina waited beside the old gate.

Find the full vertical
The word to its left is the subject: Nina. Everything to its right is the predicate.
Read along the base line
Right after the full vertical comes the verb, waited. Then look for a half vertical or a backslash. There is none, so this sentence has no direct object and no complement.
Read what hangs below the base line
Under waited, a diagonal carries beside down to a horizontal that holds gate. This prepositional phrase tells where Nina waited.
Go one level lower
The words the and old hang on slants under gate, so both modify gate.
Check your reading
Put the pieces back in sentence order. You should get the sentence you started with: Nina waited beside the old gate.

Four more marks: pedestal, chevron, dashed line, floating line

These four marks cover almost everything else you will meet. Each is taught in full on a later page, linked under its entry.

Pedestal (a stand): A stem with a small triangle at its foot, lifting a phrase or clause above the base line. It means “this whole group of words fills one slot”, and its foot stands in that slot. Feeding the ducks calms Omar. — the gerund phrase stands on a pedestal in the subject slot. She knows that we left. — the whole clause stands on one in the object slot, after the half vertical. A pedestal right after the verb, with no mark in front of it, holds a complementary infinitive, as in has to leave.
See: Gerunds · Infinitives · Noun Clauses
Chevron (a fork): A line splits into two or more parallel branches, one for each joined word. It means coordination: two subjects, two verbs or two objects sharing the rest of the clause. The conjunction sits on a dashed line between the branches. Santiago and his sister laughed. — two subjects, joined again before one verb. She washed and dried the plates. — one subject, two verbs.
See: Imperatives & Conjunctions · Compound-Complex Sentences
Dashed line: A line that connects two words on different lines. Often a conjunction sits on it, as in the chevron above. We left because it rained. — because sits on a dashed line from left down to rained. A relative pronoun is not on the line: it fills a slot in its own clause, and the dashed line joins it to the noun it refers to. The scarf that Marta knitted is blue. — that is the direct object of knitted, and a dashed line joins it to scarf.
See: Adverb Clauses · Adjective Clauses
Floating line (no connection): A short horizontal line above the diagram, attached to nothing. It holds a word that stands outside the clause’s grammar: a person being addressed (a vocative), or an adverb commenting on the whole sentence (a disjunct). Elena, we need your help. — Elena floats above the clause. Frankly, the plan failed. — so does Frankly.
See: Imperatives & Conjunctions · Adverbs

Quick check

These two sentences use the same verb: The milk tasted sour. Lucia tasted the milk. Which one has a backslash after tasted, and which has a half vertical? Why?
Answer
The milk tasted sour. has the backslash: sour describes the subject (the milk is sour), so it is a complement. Lucia tasted the milk. has the half vertical: milk receives the action, so it is the direct object. The verb is the same; the job of the word after it decides the mark.
Look at A small boat slowly crossed the lake. Which three words sit on the base line? Where do the other four words go?
Answer
The three words are boat, crossed and lake: the subject, the verb and the direct object. The other four words are modifiers, so each hangs on a slant under the word it describes: A and small under boat, slowly under crossed, and the under lake. Slowly comes before the verb in the sentence, but it still hangs under the verb.
Look at The lamp on the desk flickered. Which word does on the desk hang from, and what shape does the phrase have?
Answer
It hangs from lamp, not from the verb: the phrase tells which lamp, so it hangs from the noun it describes. The preposition on sits on a diagonal that drops to a horizontal holding desk, and the hangs on a slant under desk.
Look at Priya packed a map and a compass. Which mark shows that there are two direct objects? Where does and go?
Answer
A chevron. After the half vertical, the object slot forks into two branches, one for map and one for compass. The word and sits on a dashed line between the branches, and each a hangs on a slant under its own noun.

Summary: all ten marks

Mark	What it looks like	What it means
Base line	A long horizontal line	The core of the clause
Full vertical	Crosses the base line	Subject \| predicate (one per clause)
Half vertical	Stops at the base line	Verb \| direct object
Backslash	Leans back toward the verb	A complement follows
Slant	Hangs down to the right	A modifier of the word above
Diagonal + horizontal	A slant ending in a flat line	A prepositional phrase
Pedestal	A stem on a small triangle	A phrase or clause filling one slot
Chevron	A line forks into branches	Joined subjects, verbs or objects
Dashed line	A broken line	Connects words on different lines, often with a conjunction on it
Floating line	A short line joined to nothing	A word outside the clause

Practice on a real sentence

In Roles, choose a role, then drag across the words that play it. In Role match, match each ready-made phrase to its role. Every correct answer adds a piece to the diagram, so you build the picture yourself. Look for the chevron: after the full vertical, the line forks into two branches, one for each verb, because both verbs share the subject Barbara.

Loading the practice sentence…