1 If you warn somebody (about something), you tell them about a danger.
2 If you complain to somebody (about something), you tell them why you are unhappy about it.
3 If you apologise (for something), you say that you are sorry.
4 If you enquire about something, you ask questions about it.
5 If you recommend something (to somebody), you say why it is good.
6 If you encourage somebody (to do something), you make them feel more confident about it.
7 If you welcome somebody or something, you say you are happy about their arrival.
8 If you inform somebody (about something), you tell them facts about it.
9 If you challenge somebody, you invite them to compete with you.
10 If you comfort somebody, you try to make them feel better when they’re sad.
11 If you persuade somebody (to do something), you say things which make them want to do it.
12 If you entertain somebody, you keep them amused and interested.