February 01, 2017: WHAT CONSTITUTES A PROPER SENTENCE?
Today’s topic is prompted by a confusion regarding when a statement (i.e. a string of words) must end with a full stop (aka a “period”). Simply put, only a full sentence must end with a period, or its equivalent, such as the exclamation mark (!) or the question mark (?) as appropriate.
This blog site is dedicated to observations on the vagaries of written English in the USA. The reason for limiting it to written English is that the written form is the one used for formal communications, where ambiguities or inconsistencies degrade the meaning you wish to convey, and you get only one chance to convey that meaning and sense. One rule of formal English that has not changed over time is that you should write your prose in full sentences. So it becomes important to know when a sentence is complete, or “full.”
In what follows, explanation/elaboration from Latin is in italics. Also, we limit ourselves here to a simple sentence; in real life things get more complicated because you have, additionally, compound, complex, and compound-complex sentences; let’s call the last three “non-simple” sentences.
Except for minor exceptions (which we shall consider later) a full or proper sentence is one that has basically three parts: 1. a verb (denoting action); 2. a subject (the nominative case in Latin) which performs the action indicated by the verb and which is basically a noun or a pronoun or other parts of speech playing the role of the subject of the main verb in your sentence; and 3. an object. In “She has guts,” she is the subject, has is the verb, and guts is the object; that sentence is complete. The verb and object may be lumped together and called the “predicate”: in “She has guts,” “she” is the subject and “has guts” is the predicate.
A caveat here is that in going from conversation (live or TV) to broadcast speech (on radio) to print (newspaper/magazine) the line between informal and formal English may blur or even disappear!
Besides the sentence, other important kinds of expression are, a clause and a phrase. A clause also has a verb or verbs whereas a phrase does not. The clause and the phrase can be parts of a sentence and so play subordinate roles in a sentence. It is the inclusion of a clause and/or a phrase and/or clusters of clauses and phrases that characterize the other (“non-simple”) kinds of sentences. The reason for mentioning the clause and the phrase here is that in US English there’s a tendency to confuse them with a full sentence.
As stated, only a full/complete sentence MUST end with a period. A clause or a phrase does not need to end with a period. This is important when you write a list and wonder how to end each line. That, in my opinion, is where some writers, editors and reviewers I have encountered tend to get things wrong: You write a bulleted list consisting of phrases, and an editor says you should end each line with a period. (I encountered a reviewer who inserted periods at the ends of subject headings!)
The foregoing is, of course, grossly simplified. As stated, in real life the sentence structure can get quite complicated. However, a sentence cannot be made more simple than “subject + predicate.”) Or can it? Well, there are simple exceptions. Most common exceptions are the single words used in the interrogative sense or the exhortatory sense (vocative case): i.e., used to ask a question, to urge someone to an action, or to answer a question. Examples are, respectively, “Why?”, “Go!”, “Yes.” Each of those is considered a full sentence though it comprises only one word. Other similar but minor examples are exclamatory words (“Oh!” and “Silly!” for instance).
Finally, here is a word about phrases and especially clauses standing alone. (Note that this foregoing sentence becomes improperly constructed if we remove “here is” — because then it lacks a main verb, “is.” But that incorrect form, without “here is,” has become common or popular.)
It is incorrect English to write:
- Because we are human.
- Since he promises to pay.
- While we sleep.
- And that is bad.
- Etc.
The reason they constitute bad English is that the first word in each case is a transitional word and so what follows it is a clause and not a sentence. A transitional word is used to connect two clause, phrases, or sentences: E.g. “She smokes, and that is bad” is correct English.






