Talk

When you have a conversation, you talk (to someone) about something: ‘We talked about where we could go at the weekend.’

When there is something that you want someone to know, you tell them about it: ‘She told me about her holiday plans.’

When you use a language for conversing or communicating, you speak (NOT talk): ‘Do you speak Italian?’ ‘I didn’t know you could speak Greek.’

Talk to sb (about sth): ‘The manager would like to talk to you when you have a moment.’