Hi Pdlma iwbury,
This is how I explain the words from those song lyrics:
"wanna" becomes (I) want to ...
"gonna" becomes (I am) going to ...
"hafta" becomes (I) have to ...
Be aware of the different forms of the English language used:
1. Conversational (informal) friends, family talking together
2. Public Speaking (Formal) Speeches, speechmaking, talks, discussions
3. Written (formal) Books, textbooks, documents, newspapers
4. Written (informal) letters, email, notes
5. Media (varies) Television, Internet, Radio, magazines
There will be some overlap on these definitions. Example: some tv programs, magazines and newpapers may borrow and use conversational speech
Mangosteen