A tongue twister

Ехал Грека через реку,
Видит Грека- в реке рак
Сунул Грека руку в реку-
Рак за руку Грека- Цап!

Roughly:

Greka* went across the river,
Greka saw a fish in the river,
Greka put his hand in the river,
The fish went -- Snap!

*A diminutive of Грегорий (Gregory), I believe.


Today's word:
река - river

Historical linguistics

I recently noticed how similar Latin and Russian verb endings are:

-o / -ю
-as / -ешь
-at / -ет
-amus / -ем
-atis / -ете
-ant / -ют

Sort of renews one's faith in Proto-Indo-European.

Today's word (picked for its length):
достопримегательность (f.) - place of interest (usu. pl.)

Russian negation

Lastly, section 279 of A Comprehensive Russian Grammar states: "Нельзя combines with the imperfective infinitive in the meaning of inadmissibility and the perfective in the meaning of impossibility."

So, your first sentence, "*они пишут по-русски правильно," should read "они правильно пишут по-русски" and your second sentence, "*здесь нельзя говорят громко," should read "здесь нельзя громко говорить."

Today's word:
круг - circle