English is like one night stuff?

Once my ESL teacher told me "Keep studying and you will be surprised someday in the future that you can speak English when you wake up." Is this true? I have been studying English for half years and have accumulated thousands vocabularies, but I still don't have that sensation.
How long would it take me, an ordinary person with no extraordinary talent, to be able to understanding every word appear on regular TV?

[Tdol]

It does take a while, but you should be able to follow the TV easily within a couple of years of starting.