Why I am, but you are, and the verb itself is generally to be?

People don't like the answer “It happened historically” because it doesn't explain anything.

The techies say: give me a plate and a diagram, I want to know how the system works and how English works, then I can learn it. 

Linguists answer: first, let's study the conjugation system of the verb to be. 

Where is the logic in this system? The answer to this question is annoying: there is no logic, but there is an explanation that it happened so historically. - But I want to see a system that I can rely on as a template! 

People do not like the phrase “It happened historically” because it doesn’t explain anything.

, , , , , -, , , , , . 

I am, you are, to be? 

, () “” .

1. es- -. . 1 ...: . “”, . eimí, . ásmi (-, , , ) 3 ..: . “”, . est, . ásti. (.-. es+ti) 3 ...: . “”, . sunt, . sánti (.-. s-onti, s-enti)

2. *bhū- . . “, , ”, . fui (), futurus ()

3. wes- (ṷes -) . .: vásati (, ).

, , be – was – been.

bēon () :

1. ic eom/beo – we sind(on)/beoþ

2. þu eart/bist – ᵹe sind(on)/beoþ

3. he, heo, hit is/biþ – hie sind(on)/beoþ

,   :

1. bim (bin) birum (-un)

2. bist birut

3. ist sint

, , – . (IV - VII . ..) . ( *bhū-) , .

In Russian, of these ancient roots, the root * bhū- (to be, was, will be) and the root es- (is, the essence) remained. Nowadays we can do without a linking verb at all, and nothing.

Twenty years of working with techies has shown that they don't always trust us, but they find these excursions amusing.