To conjugate a verb means to make a systematic list of all of its various forms.  We use different forms of the same verb in situations like the change from count to counts to counted, and so on.

There are two general areas in which conjugation occurs; for person and for tense.  Conjugation for person occurs when the verb changes form, depending on whether it is governed by a first, second, or third person subject.  This gives three conjugations for any verb depending on who is acting as the subject of the verb.  For example, we have I count, you count, and he counts.  Note that only the third conjunction really shows a difference.  In addition to the above, we can have the same three persons in the plural form.

While most English verbs simply do not show extensive conjugation forms for person, an exception is the verb to be.  "To be" is conjugated for person as follows:
 

In addition to person, conjugations for tense are significant for all verbs.  All conjugations start with the infinitive form of the verb.  The infinitive is simply the to form of the verb.  From there, the verb takes on different forms depending on the tense type and time.
 

The really teachable aspects of this chart have to do with the systematic quality of the changes.  There is a formula that applies with exact regularity.  Using this formula, we can derive each conjugation.  The students can come to see something about the systematic quality of language (and the extent of unconscious knowledge that we all carry around about the system of language).

• The formula for simple type tense is  "verb + tense form."
 
The tense form is -ed for past, nothing for present, and will -- for future.

• The formula for perfect type tense is (to have + tense form) + past participle of the main verb.

Notice that in all of the perfect forms, the word counted doesn't change.  It is only the first part of the the conjugation that changes, the part with to have.  It changes from had, to have or has, to will have; but counted stays the same in all three conjugations.  In the perfect tense, the auxiliary verb is have and the main verb is whatever the verb is, in this case count.  It is the auxiliary verb that carries all of the changes in form and all of the information about tense and time.

• The formula for the progressive type tense is (to be + tense form) + present participle of the main verb.
 
The present participle is the -ing form of the verb.  Whichever tense time, the verb count is always in the -ing form.  It is only the auxiliary that changes form according to the tense time.  Again, it is the auxiliary that carries most of the information about tense.

• The formula for the perfect progressive type tense is  [ (to have + tense form) + past participle of to be ] + present participle of the main verb.
 
Only the form of to have changes in this conjugation.  The past participle of to be, i.e., been, remains the same in each conjugation, as does the present participle of the main verb, in this case, count.

Robert Einarsson.  Please visit my home page for readings in the history of traditional grammar.