Formal and Informal

• Informal language is more casual. It is used when communicating with others.
• Formal language is used when writing for professional or academic purposes like university or school assignments.. 

Informal	Formal	Informal	Formal
sorry	apologize	check	verify
tell	inform	get	receive
need	require	help	assist
ask	request	start	commence
mad	insane	go up	increase
tough	difficult	book (v)	reserve
so	therefore	choose	select
look for	seek / search	may be	perhaps
say no	reject	buy	purchase