Possible Clues:

• No-one can rule pub out, it's impossible to say
• Announce pub role -- getting worked up, it's hard to speak
• Impossible to say properly
• Non-European club reformed? It's impossible to say
• Does this explain how difficult it is to get one's tongue around this? It's hard to say!
• A clue Ben concocted about part of speech impossible to deliver
• Powerless about part of speech to church? It's not fit to deliver