Direct speech is a way to transfer the statements said by other people in writing. Reading something in Russian (either textbooks or authentic materials like newspapers and literature), you might have noticed differences in its composition.
There are four basic structures used for the composition of direct speech in Russian. And the punctuation depends on the position of the author's words and the phrase relative to each other. You should pay your attention not only on the usage of punctuation signs, but also on the usage of capital and lower case letters.
We use the first scheme, when we have a statement at first and then author's words. It can be declarative sentence, as well as interrogative or exclamative one. In all cases we use double quotation mark for the statement which begins with a capital letter like any new thought. Author's words are written with a lower-case letter and there is em dash between them and a statement.
*hereinafter, "П/п" - direct speech (statement), "А/а" - author's words.
"П", — а.
"П!" — а.
"П?" — а.
The second scheme is opposite, when at first we have author's words and then - a statement. In this case a sentence begins with a capital letter and we write two-spot after author's words. Direct speech is also written with a capital letter and double quotation mark.
The third scheme denotes a situation when author's words divide direct speech. It is more complicated case. We also use here double quotation mark and em dash, write author's words with a lower-case letter and direct speech either with lower-case or capital - it depends on what is following after author's words - comma or full point. And this depends on whether author's words are single thought or two distinct ones. In this case all structure, including author's words, is written with double quotation mark entirely.
"П, — а, — п".
"П, — а. — П"
The fourth scheme is used, when direct speech separates author's words. Here we write two-spot after author's words introducing a sentence, write direct speech with double quotation mark and regardless of whether this sentence is declarative, interrogative or exclamative, we use em dash and author's words again but with a lower-case letter.
А: "П" — а.
А: "П!" — а.
А: "П?" — а.