Past participles in the English language usually end with -ed, but slain is one exception. Why can't we have just slayed rather than that and slain, too? And why can't slain be its very own verb?

Update: I'm not familiar with Old or Middle English.


2 Answers 2


Slay has always been a “strong” verb

The reason that we today say slay, slew, slain is that it was originally a perfectly normal strong class 6 verb in Old English.

Strong verbs are those that show their past tense with a vowel mutation, like know, knew instead of *knowed which would be a weak verb (and wrong of course).

Although strong verbs are more prevalent in Germanic languages, this vowel-mutating can also be found in Romance. For example, the Spanish verb saber meaning to know has a vowel change in its preterite forms, so sabe in the present unexpectedly becomes supo in the preterite. And the Spanish verb dar meaning to give has da in the present but a surprising in the preterite. You can even see this happening all the way back in its Latin root, dare, which has dat in the present but a surprising dedit in the perfect.

So strong verbs with vowel changes in the past tense are actually pretty common. Examples of strong class 6 Germanic verbs that are still strong in English today include:

  • draw, drew, drawn
  • forsake, forsook, forsaken
  • shake, shook, shaken
  • slay, slew, slain
  • swear, swore, sworn
  • take, took, taken
  • wake, woke, woken

As you see, slay isn’t quite like the others there, being a bit like draw, drew, drawn but also a bit like lie, lay, lain, which was a strong class 5 verb instead.

That’s because slay underwent a great deal of phonetic variation and confusion in both Old and Middle English to get to us today.

In Old English slay was sléan, or northern slán, slá. Its past tense was slóg or slóh, its plural was slógon, and its past participle was slægen, slegen, or slagen. As you see, there’s already some variation all the way back in Old English.

The OED notes that:

All parts of the verb exhibit a great variety of Old English and Middle English forms, partly through natural phonetic development, and partly by assimilation to each other.

The normal Middle English infinitives are slē(n from Old English sléan, and slā(n, slō(n from northern Old English slán or from Old Norse slá; the later forms sley, slay are due to the influence of the past participle.

So that’s why it’s slay, slew, slain today.

The Historical Record of Forms

To help illustrate how tangled a history this verb has had in English, here is a summary of the OED’s tracing of its historical forms. I have omitted 98% of the actual text because those are illustrative citations.

  1. infinitive.

    • α. OE–ME slean (ME sclean, sclein), ME sleen; ME slæn, slen, slene.

    • β. OE, ME slæ, ME–15 sle (ME scle), ME–15 slee (ME sclee), ME–15 slea.

    • γ. (northern and Scottish) OE, ME slan, ME slane; OE, ME slaa, OE, ME–16 sla (ME scla), 15–16 slae, slea.

    • δ. ME slon, slone; ME–15 slo (ME sclo), ME–15 sloo, ME–16 sloe.

    • ε. ME slaȝe, slayn, ME–15 slaye, 15 slaie; ME–16 sley (15 sleye), ME– slay (15 sleay).

  2. present indicative.

    • a. 1st person singular (also subjunctive) OE slea, OE, ME slæ, ME sle, 15 slee; 15 sley(e, slaye, 16– slay.

    • b. 2nd person singular

      • α. OE sles, slaes, ME slees; ME slaas, slos.

      • β. OE slehst, slægst, ME sleast, sleest; ME slast, 15– slayest (poetic slay’st).

    • c. 3rd person singular

      • α. OE sliehð, slihð, slyhð, slæhð, ME slehð, slekþ.

      • β. OE slaeð, ME sleað, slað; OE sleð, ME sleþ, ME–15 sleth, ME slethe; ME sleeþ, ME–15 sleeth; OE slaes, ME sles(e, ME slees, 16 sleas.

      • γ. (northern and Scottish) 3rd person singular ME slaþ; ME slas, slase, ME–15 slaes, slais. Also ME sloð, sloys.

      • δ. ME slaȝþ, sleith, ME–15 sleyth, 15 sleythe, sleayeth, 15– (now poetic) slayeth; 15–16 slayes (Scottish slayis), 16– slays.

    • d. plural.

      • α. OE–ME sleað; ME slen, sleen (scleen); ME–15 slea, sle, slee (ME sclee); also northern ME slees.

      • β. ME slaȝe(ð, 15 sleye, slaye, 16– slay.

      • γ. (Also subjunctive) ME sla, slaa, slo(e.

  3. present subjunctive (2nd and 3rd person singular).

    • α. OE slae, OE, ME slea, ME–15 sle, ME slee.

    • β. northern ME sla, slo.

    • γ. 15 slaye, 15– slay.

  4. imperative.

    • α. OE sleh, ME sleih, sle, ME–15 slee, 15 sley; OE sleah, sleage, ME slea; OE slyh, ME slygh.

    • β. singular ME, 15 sla; ME slo, 16 Scottish sloe. plural ME slas, slays; slo, slos.

    • γ. 15 slaye, 16– slay.

  5. past indicative.

    • α. 1st and 3rd person singularOE, ME sloh, ME slohw; OE slog, slogh, ME sloȝ, slooȝ (ME sloþ), ME sloȝe; ME slog, slogh (ME sloght), sloghe, sloch; ME slo. 2nd personOE sloge, ME sloȝe.

    • β. singular ME slowe (ME sclowe), ME sloue; ME slow (ME sclow), ME sloow, slou (sclou).

    • γ. singular ME slouh, slowh, slouȝ, slowȝ(e; ME slough, sloughe, slowgh(e. plural ME sloughen; ME slowȝe, slowhe, sloughe; ME slouȝ, slough.

    • δ. singular ME sluȝ, sluȝe, 15–16 slue; ME slewȝ, Scottish sleuch (sleucht), 15 scleuȝe; ME– slew, ME–15 slewe. Also 2nd person 15–16 slew’st.

  6. past subjunctive OE sloge, plural slogen, ME sloȝe, sluȝe, slowe.

    • α. (a) OE geslægen, geslegen, ME i-slæȝ en, i-sleien, i-slein, i-, y-slayn, y-sclayn, y-slayne, 15 y-slaine.

    • β. ME i-, hii-sleȝe, i-slehȝe; ME sleie, sleye, slaye, slay, scley.

    • γ. OE geslagen, ME i-slaȝen, i-sclawen, i-slawen, y-slawen; ME slaȝen, slawen, slaun, slawn.

    • δ. ME i-, y-slaȝe, i-slawe, ME–15 y-slawe; 15 y-slaw; ME slawe (ME sclawe).

    • ε. ME i-slæn, sleen, 15 slene.

    • ζ. northern and Scottish ME slan, ME–15 slane, 15 y-slane.

    • η. ME slon, ME–15 slone, ME sloon.

Isn’t that incredible? Aren’t you relieved that we’ve been left with nothing more complicated than the standard slay, slew, slain today? I know I sure am!


Why is slain a past participle of slay?

Because it derives from Old English.

Modern English comes from a mixture of languages, French, Latin, Greek and Germanic.

Old English is a Germanic language. The verb "to slay" has changed over time but is Germanic in origin. Today it is called an irregular verb because it does not not have the regular inflections you might expect.

Present tense in modern English

I/you/we/they slay

he slays

Simple past (modern)

I slew, etc.

Participle (modern)

I have slain, etc.

Historical note

If you go back to the 1600s when the King James Bible was published, you'll find an older form that is described in the following link. It includes "thou slayest", and "he slayeth".

conjugation of slay

Already in modern day English you may see "slayed" used as simple past and as past participle among people who don't have a classical education. It is quite possible that this and other irregular verbs will become regularized as the century progresses.

  • Where (Early) Modern English has thou slayest or thou slay’st, Old English once had þú slægst using a g that perforce became a ȝ in Middle English and thence a simple y in Modern English. It really all makes fine sense viewed diachronically even if it just completely buggers the brain under synchronic analysis uninformed by history. :)
    – tchrist
    Sep 27, 2020 at 22:15
  • 1
    A classical education? Jun 17, 2021 at 23:00
  • @EricVelazquez A classical education included first and foremost in the Grammar section of the trivium a command of Ancient Greek and Latin. :)
    – tchrist
    Jun 17, 2021 at 23:54

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