There are almost one million immigrants living in the UK who don't speak very good English.

This two-part series follows four first-generation immigrants as they try to learn the language for the first time.

Each one is taught by ordinary British people, with each immigrant living for a week with a family, who apply their own unique ways to try and help their guest.

In episode one, the four immigrants, who entered Britain over a year ago, come originally from Poland, Colombia, China and the Democratic Republic of Congo. None of the four has managed to learn English so far.

Now, each of them has their own special reason for wanting to learn: for some it means more opportunities for work, and the chance of a fresh future for them and their family; while for others it offers a possible end to loneliness.

Why Don't You Speak English? provides the immigrants with a crash course for learning English, while for the host families it offers a first-hand insight into immigration - how do communities exist in the UK where virtually no English is spoken, and what can the British families do to help their new friends integrate better?

Why Don't you speak English?: Channel Four Tuesday 23 July @ 9pm.