Possible Clues:

• Letter pronounced while breathing out
• Give voice to Beethoven's fifth
• Like Hook and his sound beginning
• Some folk carelessly drop this character in the middle of nowhere
• East-ender's house, say, might not have one
• Sound one's Hs, as with Hook?
• Sound of puff adder's fellow creature, enraged
• Say the 'h' in 'historical,' say
• Like illegal broadcaster to pronounce his aitches
• Suck like Blackbeard?