Talk:Airbending/@comment-218.214.23.177-20110721064238/@comment-96.251.95.43-20110727010008

Soundbending is hinted at when Aang amplifies his voice and whistle. But all of these specialty forms (lightning, metal, and blood) require that someone discovers and then teaches the technique. There may have been unique Airbenders with the ability that didn't pass it on (like Combustion Man's technique). It might also just never have been figured out.

Thousands of Earthbenders probably tried to bend Metal, but it required Toph fine-tuning her Seismic Senses to be able to discover the technique. Lightning is equally difficult and rare, it's only been mastered by 3 living characters, all of whom probably learned it from an original source. We don't see Lightning as being as special as Metal because more than one person does it, but it's just as specialized. Same goes for Bloodbending, a secret Southern technique that would have been lost for ages if Hama hadn't forced Katara to learn it. Now it's up to her to teach it, or it will die out, just like the ancient Firebenders' style nearly died out until Zuko and Aang found the hidden village and last dragons.