Breakdown of Мама сказала, что из‑за старой проводки может появиться искра.
Questions & Answers about Мама сказала, что из‑за старой проводки может появиться искра.
In Russian, subjects are often omitted when they are clear from context, but in this sentence Мама is named explicitly because she is the person doing the speaking.
Russian also often uses family words like мама, папа, бабушка almost like names in everyday speech. So Мама сказала sounds very natural and means Mom said...
You could say Она сказала, but that would mean She said, and it would only work if it were already obvious that she = Mom.
Сказать and говорить can both relate to speaking, but they are used differently.
- сказать = to say, to tell, to state something once, as a completed act
- говорить = to speak, to talk, or to say in a more ongoing/repeated sense
Here, Мама сказала, что... means Mom said that... as one completed statement, so сказала is the natural choice.
Also, сказала is the past tense feminine singular form, because мама is grammatically feminine.