“Cheer”, “Cheer on” and “Cheer up”

The verb “cheer” and the phrasal verbs “cheer on” and “cheer up” may sound similar but they have very different meanings.
To “cheer” means a loud cry that shows approval or excitement.

“Everyone in the audience cheered loudly after the stellar play.”

“The baseball stadium was overwhelmed with the sound of cheering fans.”
To “cheer on” means to encourage someone by cheering (the verb we just talked about). “The crowd cheered on the final runner in the marathon.”

Again this involves loud cries, and is usually used at competitions. It usually happens in crowds, but a single person can do it too:

“The rest of the audience was silent, but Thomas stood up and loudly cheered on his daughter during the talent show.”

To “cheer someone on” with more mundane tasks is possible, but would be a strange social situation.

“Mary’s boss cheered her on as she worked” would have the boss loudly yelling something like “Hey you can do it!” to his employee.
“Cheer up” is a little different. It means to become happier, and is used when someone is sad.

“I was lonely my first week at uni, but a call from my mom cheered me up.”

“After his daughter lost the talent show Thomas bought her an ice cream to cheer her up.”
If you tell someone to “Cheer up” it means you think they are sad and are telling them to try being happy.
A: “I’m sad that we are moving to a different city.”
B: “Cheer up! You’ll make great new friends quickly.”

Politeness in English

Since there is no official “Polite Speech” or “Casual Speech” in English it is sometimes difficult to know how to talk to your superiors (bosses, professors) or elderly people.
First of all be careful not to use their first name. If their name is John Smith or Jane Smith it is best to call them Mr. Smith or Miss/ Mrs. Smith. Or you can call them “sir” or “ma’am”. If they are a professor, as in they teach at a University and have a PhD, then you can call them “Professor Smith” or just “Professor”.
Note: Never call a teacher “Smith Teacher”, “Teacher” is not a title in English, only the name of a job. “Mr / Miss / Mrs” works best.
Secondly, try to avoid slang and casual expressions
“Hey John, what’s up?” is not very polite for an older or distinguished person.
“Hello Mr. Smith, how are you today?” is much better.
Some bosses and professors don’t like the overly polite language, as they feel it distances them from others. So they may invite you to call them by their first names.
“Hello Mr. Smith, did you have a good weekend?”
“Oh please, just call me John.”
In these situations you can use their first names after being given permission, but it is still good to avoid slang and overly casual phrases.