Very often Russian language learners can be met a common mistake in the proper use of synonyms of the verb "ГОВОРИТЬ".
There are several versions of this verb. Let's consider the main ones on examples.
СКАЗАТЬ
It is used when it is necessary to inform the interlocutor or group of people about any information. This can be a short news of a person, an instruction to do something, or the transmission of someone's words.
Папа сказал о задержке нашего рейса и возможной замены билетов. – [Pápa skazál a zadérzhki náshva réjsa i vazmózhnaj zamény bilétaf.] - Dad said about the delay of our flight and the possible replacement of tickets.
ГОВОРИТЬ
This verb is used when there is one or more participants in a conversation. Its use implies a longer monologue or dialogue than in the first case.
За круглым столом мы говорили о многих проблемах. – [Za krúglym stalóm my gavaríli a mnógikh prablémakh.] – We talked about many problems at the roundtable.
РАССКАЗЫВАТЬ
When we want to transmit information in the form of a story, tale, verse, events etc, we use this verb. One participant shares information with one, several, or a group of interlocutors.
Моя дочь очень любит сказки, которые ей рассказывает перед сном её няня. – [Mayá doch′ óchin′ lyúbit skáski, katóryye yej raskázyvayet péret snom yeyó nyánya.] - My daughter loves the fairy tales, that her nanny tells her before going to bed.
БОЛТАТЬ
This verb refers only to spoken language. Implies an easy dialogue of well-known people (friends, relatives, etc.). It is a synonym for the verb «ГОВОРИТЬ».
Если ты свободен, мы можем поболтать сейчас по скайпу. – [Yésli ty svabódin, my mózhim pabaltát′ sijchás pa skájpu.] – If you are free, we can chat now on Skype.