Complex sentence: The name is interpreted as "he lives!" or the imperative "live!" that he added to his Yakama name, Chtu-Tum-Nah which he translated as "Strongheart".
Split into simpler sentences: The name is interpreted as "he lives!" or the imperative "live!". He added the name to his Yakama name, Chtu-Tum-Nah which he translated as "Strongheart".