English Translation
You sound surprised.
I think the translation should be “you seem surprised.” or even “you look surprised.”
Not necessarily. “You seem surprised.” or “you look surprised.” are indeed other sentences that translate to “Tu as l’air surpris”, but there isn’t another translation (or at least I cannot think about any) to specifically talk about sounding surprised. So, to me, the translation “You sound surprised” → " Tu as l’air surpris" is correct.