When is it necessary to use a capital letter in the beginning of the sentence?

Question

In English we have to use a capital letter in the following cases:

• Beginning of sentence
• Names (people or places)
• Pronoun first-person singular (I)

What are the rules for capital letters in Russian language comparing to these three rules in English?

Answer 1

Basically, capital letter is required in the beginning of a sentence and in names (people, places, books, etc.).

There is a tricky case with singular "вы", which can be capitalized to show respect (note that plural "вы" is capitalized only in the beginning of a sentence).

Also with multi-word names (e.g. name of a book), only first letter is capitalized, not first letter of each word as in English.

Another difference with English will be that not everything that considered to be a name in English is considered to be a name in Russian. For example, names of languages and nations and are not capitalized in Russian. I think it might have to do something with most of those being adjectives in Russian (though it's just an opinion).

Answer 2

Personal pronoun I is never capitalised (unless positioned at the beginning of a sentence):

Я изучаю китайский язык, и чем больше я его изучаю, тем больше у меня вопросов.

Names of countries are capitalised, but not names of nations and/or languages (it used to be so a couple of centuries ago, but not nowadays). Forms of address and titles are not capitalised, either.

Из всех языков, пани и панство, мадам, мадмуазели, месье, леди, джентльмены, дамы, господа и товарищи, мне наименее симпатичны английский и русский, а из всех известных мне людей наименее вежливы в обиходе - носители советского русского.

Days of weeks and months are not capitalised:

Сегодня - вторник, двадцать пятое апреля.

Abstract nouns (mainly those capitalised in modern English to imitate archaic style and/or to express 'philosophical uniqueness' of the concept they are referring to, or those normally capitalised in 'capitalisation boom' of the 17th-18th centuries following Hart's recommendation are not capitalised, either):

Относительная истина не противоречит абсолютной истине.

As for words for G-d, deities and religious holidays / events, their capitalisation is guarded either by the rules applied for personal names or by a writer's personal beliefs.