well when it comes to Arbic that's used in book which called فصحة ( fosha ) it differ somehow than arbic slang which is used by public 

when you meet someone in street you can say كيف حالك ؟ (keif halek ) but it would be alittle bit wired because it's not the slang that normal people use  so you can say ازيك ؟ (azyek ) 

and you can answer تمام - كويس so it's a slang 

if you want to say لا شيء which mean nothing you can say it ولا حاجة 

i watch tv ( انا بتفرج علي التلفزيون ) 

i want = عايز  in fosha it's اريد (ored )

today = اليوم (fosha ) = النهارده (slang )

yesterday = امس fosha = امبارح (slang )

tomorrow = غدا ( fosha ) = بكره (bokra -slang )

there is alot of words on that way you can ask about the slang of a sentence and i would with pleasure tell you

and finally don't annoy and distract yourself should i learn fosha or slang !!just go on your way and everything will come by practise as long as you are intersted