Вкаких случаях ставится speak say tell

To speak – говорить, разговаривать (больше как физическое действие)   To speak a language:  - Tom speaks English. To speak to/with somebody:  - Mark never speaks to a stranger.
 To say – сказать (что?)   To say something:  - Jack says that he is from UK. To say to somebody: - Joeys said to his teacher that he wouldn`t be late anymore.
To tell – сообщать, рассказывать (кому? – что?)   To tell somebody (about) something: - Tom is telling his friend a funny story.