In short

Every Greek verb has two stems. You already know the continuous one, because it is the present tense you learned to conjugate: γράφω, αγοράζω, μιλάω. This lesson builds the second one, the perfective (συνοπτικό) stem, which is the form Greek uses when an action is viewed as one whole event.

The machinery is almost entirely mechanical. The perfective stem of a first-conjugation verb ends in -σω, -ξω or -ψω, and which of the three you get is decided by the consonant sitting in front of the present ending: γράφω has a φ, so it becomes γράψω. Second- conjugation verbs take -ήσω, and a small group takes -έσω or -άσω: μιλάω becomes μιλήσω, μπορώ becomes μπορέσω.

Then there is a short list of very common verbs that do not derive their second stem at all: it is either a different word or the same word reshaped past recognition. βλέπω becomes δω, λέω becomes πω, τρώω becomes φάω, βρίσκω becomes βρω, παίρνω becomes πάρω. There are about a dozen of these and you will meet all of them in your first week of speaking, so learn them as pairs from the start.

One warning that governs the whole lesson: none of these forms is a sentence. γράψω on its own means nothing to a Greek ear. It is a building block that waits for a word in front of it, and those words come in the next lessons.

The rule

1. The perfective stem is derived from the present stem, not learned separately. Strip the present ending -ω and look at the last consonant of what remains. That consonant decides the perfective ending.

2. First conjugation, three outcomes.

• A dental or σ-type stem (mostly the verbs in -ζω, plus -θω, -τω) gives -σω: αγοράζω, αγοράσω.
• A labial stem (π, β, φ) gives -ψω, because the labial fuses with the σ: γράφω, γράψω. Everyday verbs in -εύω do the same: δουλεύω, δουλέψω. (A second, equally large group of -εύω verbs keeps the -ευ- and gives -εύσω instead, as in απαγορεύω, απαγορεύσω; none of those are A1 words.)
• A velar stem (κ, γ, χ, and the -χνω verbs) gives -ξω, by the same fusion: ανοίγω, ανοίξω.

There is a real sound law behind this, not just spelling: π/β/φ + σ is written ψ, and κ/γ/χ + σ is written ξ. Greek never writes the two letters side by side, which is why γράφσω is impossible.

3. A group of verbs in -νω loses the nasal. φέρνω, φέρω drops the -ν-; μαθαίνω, μάθω and καταλαβαίνω, καταλάβω drop the whole -αιν-. The perfective here is shorter than the present, not longer. A few verbs of the same shape keep the -ν- and only shorten -αίνω to -άνω, as in πεθαίνω, πεθάνω. (Verbs in -ώνω are not in this group: they behave regularly and give -ώσω, as in πληρώνω, πληρώσω.)

4. Second conjugation takes -ήσω, whichever of the two second-conjugation patterns the verb follows: μιλάω, μιλήσω; αγαπώ, αγαπήσω; οδηγώ, οδηγήσω. A small, high-frequency minority takes -έσω (μπορώ, μπορέσω) or -άσω (περνάω, περάσω). These have to be memorised one by one, but there are only a handful of them.

5. About a dozen everyday verbs have an unpredictable perfective stem. In a few of them it is genuinely suppletive, taken from a different root: βλέπω, δω. λέω, πω. τρώω, φάω. In the rest the root survives but is reshaped past recognition: δίνω, δώσω. πίνω, πιω. παίρνω, πάρω. Either way, no rule will get you there. These are not separate verbs, and a dictionary will not list δω as its own headword; it is the other half of βλέπω, exactly as English “went” is the other half of “go”.

6. The perfective form never stands alone. In this lesson every perfective form is cited bare, as γράψω, δω, μιλήσω, and that bare citation form is called the dependent because it depends on something else. It cannot be a sentence, it cannot be an answer to a question, and it cannot be a command on its own. The words that license it (θα, να, and the endings of the past tense) are the subject of the lessons that follow.

7. Three very common verbs have no perfective stem at all: είμαι, έχω and ξέρω. They describe states, and a state has no natural end point, so there is simply nothing to build. If you find yourself hunting for the perfective of είμαι, stop: it does not exist.

Forms & patterns

First conjugation: the three endings

Note that the -ζω verbs split: most give -σω, but παίζω and αλλάζω give -ξω. That split is lexical and has to be learned with the word.

Verbs in -νω that shorten the stem

Second conjugation

The unpredictable list

πάω is a special case: the same form serves as both stems, so context alone tells you which aspect is meant.

The dependent conjugates in all six persons

The perfective stem is not a frozen word. It carries the ordinary personal endings, the same ones you already use in the present.

The short irregular forms take the same endings. Where the stem has no vowel of its own (δ-, π-, βρ-, μπ-, βγ-), the accent has nowhere to sit but the ending: δούμε, δείτε. Forms that already carry a stressed vowel - πάω, φάω, πάρω - keep the accent where it is: πάμε, φάτε, πάρουμε.

The verbs with no perfective stem

Examples

Read each row as a pair: the word you already know, and the second stem you are adding to it today. The perfective is given bare, in its dependent citation form.

Common mistakes

• γράφσω -> γράψω - Greek never writes a labial next to σ; φ plus σ is spelled ψ, and the same fusion turns π and β into ψ too.
• ανοίγσω -> ανοίξω - the velar version of the same law: κ, γ or χ plus σ is written ξ.
• μιλάσω -> μιλήσω - the second conjugation does not just bolt -σω onto the present vowel; the regular ending is -ήσω.
• μπορήσω -> μπορέσω - μπορώ is one of the few second-conjugation verbs taking -έσω, so it has to be memorised against the -ήσω default.
• περνήσω -> περάσω - likewise περνάω belongs to the small -άσω group.
• μαθαίνσω / μαθήσω -> μάθω - this class shortens instead of lengthening: the -αιν- of -αίνω simply disappears.
• βλέψω -> δω - βλέπω has no derived perfective at all; its second stem is the unrelated δω, and no rule will get you there.
• Treating δω, πω, φάω, βρω as separate verbs -> they are the second half of βλέπω, λέω, τρώω, βρίσκω - always store them as a pair, the way English stores “go, went”.
• δω used as a whole sentence -> the bare dependent is never a sentence - it is a form waiting for a word in front of it, so on its own it communicates nothing.
• είσω / ξερήσω -> είμαι and ξέρω have no perfective stem - είμαι, έχω and ξέρω name states, and states have no single-event form to build.

Tips

• Learn the second stem at the same moment as the verb, never later. Write every new verb in your notebook as a pair, γράφω / γράψω, and you will never have to reconstruct it under pressure.
• Say the fusion out loud once and it sticks: π, β, φ plus σ makes the sound ψ; κ, γ, χ plus σ makes the sound ξ. Your mouth is doing the rule already, the spelling just records it.
• The default for the second conjugation is -ήσω. Keep a short private list of the exceptions you actually use (μπορέσω, περάσω, φορέσω, γελάσω) instead of trying to learn a full table.
• The irregular forms are short, and short means frequent. δω, πω, πάω, φάω, βρω, πάρω, μπω, βγω are the eight you will need first; drill exactly those eight until they are automatic.
• Watch the accent in the short plurals: δούμε, πείτε, βρούμε, μπούμε carry the accent on the ending, unlike γράψουμε and μιλήσουμε, which keep it back on the stem.
• Do not try to use these forms yet. They are inert until you add the word that carries them, which is θα for the future and να for the subjunctive; both are coming in the next two lessons.
• If you cannot remember a perfective stem in the middle of a sentence, fall back on the continuous stem. You will sound slightly off, but you will be understood, which is more than a made-up form like γράφσω achieves.