hoshyhoshy,
Your written English is pretty good.
Spoken english will develop one your ear has been exposed to it in a daily environment, also, watch english language films, once you can follow the dialogue you will be fine (rom-coms or romantic comedies are good way, they tend to have less 'street speak' and often use dialogue for nuance. you may not get it all, but the objective is to improve your english language skills).
You're doing fine.