Possible Clues:

• Urge initially to understand an Indo-European language
• Promote union in Indo-European language
• "Shut up" — that's dreadful language
• Shut up! That's bad language
• Give two, by the sound of it, a shove, in a manner of speaking (6)
• 'Shut up', as voiced in Afghanistan
• Try to sell solver foreign language
• Use the tongue to give a shove to two, by the sound of it
• Give a shove to the pair of them, by the sound of it, in a manner of speaking
• Afghan ordered to shut up