Verb Conjugation

It is usual to say that there are 2 different types of verbs in ancient Greek, with different conjugation patterns:
  • -ω verbs and
  • -μι verbs
The differences are not that enormous, just a tad confusing. Especially because -μι verbs are different from -ω verbs in the present tense complex only. But even within this there are similarities between both groups as far as formation of subjunctive and optative is concerned.
In short, if we know our -ω verb conjugation, there are very few new things we've go to learn
 

Thematic versus A-thematic

  • verbs insert a vowel (ε or ο) between the stem and the personal ending. This vowel is called thematic vowel. The word itself looks like it was derived from τίθημι (tithemi = to put, place).
     
  • -μι verbs, in the present tense complex, do not insert such a vowel and are therefore also sometimes called a-thematic (privative α meaning no extra vowel inserted). The personal endings are added straight to the stem of these verbs. In the present tense complex.
    Unfortunately this term "athematic verbs" is misleading, because their conjugation is only athematic in most of the present tense.
    In the aorist tense complex only 4 -mi verbs (and their compounds) have athematic 2nd aorists, but so do quite a few -ω verbs.
    And the passive aorist of all verbs is athematic.
 
To make the difference "thematic versus athematic" clear, compare the thematic imperfect of ἀπο-λύω (I release, let go) with the a-thematic imperfect of ἀπ-όλλυμι (I lose, destroy, kill).
I have chosen the imperfect because this is where the thematic vowel is most clearly discernible. (In the present tense contractions between thematic vowel and endings confuse the issue somewhat.)
And it also shows quite clearly that ο is used before μ and ν and
And it also shows quite clearly that ε before all else.

Compare:

 Imperfect 
was releasing
thematic
 Who? was losing
a-thematic
ἀπ έλυ ο ν I ἀπ ώλῡ ν
ἀπ έλυ ε ς you (sg) ἀπ ώλῡ ς
ἀπ έλυ ε    he, she, it   ἀπ ώλῡ  
ἀπ ελύ ο μεν we ἀπ ώλυ μεν
ἀπ ελύ ε τε you (pl) ἀπ ώλυ τε
ἀπ έλυ ο ν they ἀπ ώλυ σαν
 
You may have noticed that I did mark the ypsilon υ with a macron in the singular, but not in the plural. That is another difference between thematic and athematic verb conjugations:
In the present indicative, imperfect and imperative, active voice only, the stem-vowel is long in the singular, but short in the plural of -μι verbs. As we'll see lower down on this page.
 
There are 3 groups of -μι verbs:
  • -υμι: e.g ἀπόλλυμι (to lose; to destroy)
  • -ημι: the -η/-α class: e.g. ἱστημι (to make stand) and some others
    -ημι: the -η/-ε class: τίθημι (to set up)
    -ημι: the -η/-ε class: ἵημι (to release, throw, hurl...)
  • -ωμι. Only one verb: δίδωμι (to give)
     
  1. They are different from -ω verbs in the present tense only!
  2. They all have the same personal endings as -ω verbs but directly attached to the stem
  3. Their stem vowel is long in the active voice singular of
    i) present indicative,
    ii) imperfect and
    iii) imperative ,
    short in all the other forms. With just an active present participle seemingly playing odd man out (long masculine and feminine endings due to contraction of short stem with participle ending, short neuter).
     
     Note 
    The subjunctive (active and middle/passive, both present and aorist) seems to be real exception though. Compare δίδωμι I give) to δηλόω (I make clear)
 
Compare:
 
 Present Indicative Active 
-ω -υμι -ημι (η/α) -ημι (η/ε) -ωμι
παιδεύ ω   δείκνῡ μι   ἵστη μι   τίθη μι   δίδω μι
παιδεύ εις   δείκνῡ ς   ἵστη ς   τίθη ς   δίδω ς
παιδεύ ει   δείκνῡ σι   ἵστη σι   τίθη σι   δίδω σι
παιδεύ ο μεν   δείκνυ μεν   ἵστα μεν   τίθε μεν   δίδο μεν
παιδεύ ε τε   δείκνυ τε   ἵστα τε   τίθε τε   δίδο τε
παιδεύ ουσιν   δεικνύ ασιν   ἱστά ασιν   τιθέ ασιν   διδό ασιν
 
 Note 
  • Of course, it is not ἱστάασιν but ἱστᾶσιν. Because α + α contracts to long ᾱ, circumflex ᾶ if stressed. Like here.
  • The other difficult child ἵημι (release; hurl) is inflected exactly like τίθημι:
    ἵημι, ἵης, ἵησι, ἵεμεν, ἵετε but ἱᾶσι, not ἱέασιν (contraction!)
 

 

 Present Indicative Middle/Passive 
-ω -υμι -ημι (η/α) -ημι (η/ε) -ωμι
-ομαι -υμαι -αμαι -εμαι -ομαι
παιδεύ ο μαι   δείκνυ μαι   ἵστα μαι   τίθε μαι   δίδο μαι
παιδεύ ῃ *   δείκνυ σαι   ἵστα σαι   τίθε σαι   δίδο σαι
παιδεύ ε ται   δείκνυ ται   ἵστα ται   τίθε ται   δίδο ται
παιδευ ό μεθα   δεικνύ μεθα   ἱστά μεθα   τιθέ μεθα   διδό μεθα
παιδεύ ε σθε   δείκνυ σθε   ἵστα σθε   τίθε σθε   δίδο σθε
παιδεύ ο νται   δείκνυ νται   ἵστα νται   τίθε νται   δίδο νται
 
*
It should of course be παιδεύ ε σαι.
But, after dropping the intervening σ, παιδευ ε αι contracts quite naturally to either παιδεύει or παιδεύῃ. Thematic vowel incorporated into the contraction!