The second person singular verb ending is -(e)st. In the present tense, it works more or less like the third person singular ending, -s:Â
I sleep in the attic. Thou sleepest in the attic. He sleeps in the attic.
I love pickles. Thou lovest pickles. He loves pickles.
I go to school. Thou goest to school. He goes to school.
The -(e)st ending is only added to one word in a compound verb. This is where a lot of people make mistakes:
I will believe it when I see it. Thou wilt believe it when thou seest it. He will believe it when he sees it.
*thou willst believest it! NOPE! This is wrong
If youâre not sure, try saying it in the third person and replacing the -(e)st with -s:
*He will believes it when he sees it. ALSO NOPE!Â
In general, if thereâs one auxiliary, it takes the -(e)st ending) and the main verb does not. If there are multiple auxiliaries, only one of them takes -(e)st:
I could eat a horse. Thou couldst eat a horse. He could eat a horse.
I should go. Thou shouldst go. He should go.
I would have gone. Thou wouldst have gone. He wouldst have gone.Â
You can reduce the full -est ending to -st in poetry, if you need to drop a syllable:
thou sleepst, thou lov'st.
In some common wordsâmostly auxiliary verbs, or what you might have learned as âhelping verbsââthe ending is always reduced:
I can swim. Thou canst swim. He can swim.
Sometimes this reduction takes the last consonant of the stem with it:
I have a cow. Thou hast a cow. He has a cow.Â
Or reduces the -st down to -t:
I must believe her. Thou must believe her. He must believe her.
I shall not kill. Thou shalt not kill. He shall not kill.
However! UNLIKE the third-person singular -s, the second person -(e)st is ALSO added to PAST TENSE words, either to the past stem in strong (irregular) verbs or AFTER THE -ed in weak (regular) verbs:Â
I gave her the horse. Thou gavest her the horse. He gave her the horse.
I made a pie. Thou madâst a pie. He made a pie.
I wanted to go. Thou wantedst to go. He wanted to go.
This is different from the third person!
*He gaves her the horse. He mades a pie. He wanteds to go. SO MUCH NOPE!
Itâs not wrong to add -(e)st to a long Latinate verb in the past tense, but itâs unusual; itâs much more common to use a helping verb instead:
I delivered the letter. (Great!)
Thou deliveredst the letter. (Not wrong, but weird)
He delivered the letter. (Great!)
I did deliver the letter. (Normal if emphatic, or an answer to a question; otherwise, a little weird.)
Thou didst deliver the letter. (Great!)Â
And a couple last things:
1.) Third-person -(e)th is mostly equivalent to and interchangeable with third-person -s:
I have a cow. Thou hast a cow. He hath a cow.
I love her. Thou lovest her. He loveth her.
I do not understand. Thou dost not understand. He doth not understand.
HOWEVER! Third-person -(e)th, unlike -s but like -(e)st, can, sometimes, go on STRONG past-tense verbs:
I gave her the cow. Thou gavest her the cow. He gaveth her the cow.
This never happens with weak verbs:
*He lovedeth her. NOPE NOPE NOPE!
And even with strong verbs, from Early Modern (e.g., Shakespearean) English onward, itâs quite rare. But you will see it from time to time.
2.) In contemporary Modern English, we invert the order of subjects and auxiliary verbs in questions:
Will I die? I will die.Â
Has she eaten? She has eaten.
If thereâs no auxiliary, we add oneâdoâand invert that:
Do you hear the people sing? You (do) hear the people sing.
In Early Modern English, this process was optional, and mostly used for emphasis; all verbs could be and were moved to the front of the sentence in questions:
Hear ye the people sing? (Or singen, if weâre early enough to still be inflecting infinitives.)
Do-support was also optional for negatives:
I donât like him. I like him not.
Thou dost not care. Thou carest not.
She does not love thee. She loves thee not.
3.) Imperative verbs never take endings:
Give me thy hand. Take thou this sword.Â
4.) Singular âyouââthat is, calling a singular person by a plural pronounâarose as a politeness marker; and âthouâ fell out of use because it eventually came to be seen as impolite in almost all contexts. In general, once singular âyouâ comes into use, it is used for addressing
people of higher social status than the speaker
or of equivalent status, if both speakers are high-status
anyone the speaker wants to flatter
people of lower social status than the speaker
family and intimate friends
anyone the speaker wants to insult
It is safer to âyouâ someone who doesnât necessarily warrant âyouâ than to âthouâ someone who does.
5.) And finally, that âyeâ? Thatâs the nominative form of youâthe one thatâs equivalent to âIâ or âwe.âÂ
I  â thou â he/she/it  â we â ye â they
Me â thee â him/her/it â us â you â them
My â thy â his/her/its â our â your â their
Mine â thine â his/hers/its â ours â yours â theirs
Any time youâre using âthouâ for the singular, the second person pluralâ âyâallââ declines like this:
ye:Â Ye are all a bunch of weirdos.
you: And I love you very much.
your: This has been your grammar lesson.
yours: This grammar lesson is yours.Â