What you mean is that not everyone who uses the word knows what it means. "Sentient" comes from the Latin "sentire," which means "to feel" or "to sense." Hence, to be sentient is to be capable of sensing or feeling. Nobody who knows what the word means can confuse it with self-awareness or sapience. Here are all the glosses in the
Oxford English Dictionary:
sentient = having the power of sense perception.
Anyway, Hung's confusions are not just verbal. He says that "Most scientists think animals lack reasoning and the ability to percieve what is going on in their surroundings." "Ability to perceive what is going on in their environment" would describe sentience, which does not require or imply reasoning ability. No scientist competent to investigate animal behavior can possibly believe that animals lack the ability to perceive what is going on in their environment.