The language is controlled by the TV, depending on the model of Samsung TV the menu you need to go may be slightly different to that described.
The two main ways of changing the language are:
If you cant find the option in the menu, or continue to have issues please let me know the model number of your Samsung TV and I will look to provide you specific instructions for your Tv.
For this model of TV you need to press the d.Menu button on the remote control which takes you to the digital TV menu.
From the menu screen, select the preferences sub menu (second icon on the left hand side).
Change the 'preferred audio language' to English.
Press OK \ Enter on the remote.
If you continue to have issues, navigate to the channel you wish to watch in English, then press the d.menu button on the remote.
Select the sub menu Features, which is the third icon on the left hand side.
Select Audio Language
Select English (if English is not listed, the channel does not support this language).
Repeat the process for each channel you wish to watch in English.
Please let me know if you continue to have issues.
Unfortunately we cant connect to your model of TV.
Can you confirm what you mean by DNLe Demo, when does this appear on the screen?