How can I ask about a person's specialty?


I'm learning Japanese from a book, and it says that "specialty" is
ご[専門]{せんもん}, but Japanese speakers can't seem to understand me if I use this
word.

How can I correctly write 「ご専門は何ですか。」 ("What's your specialty?") in Japanese?




ご専門は何ですか is a perfectly natural way of saying "What's your specialty?", but
this question would make sense only to professional scholars, physicians and
such. You would expect answers like "algebraic topology", "plasma cosmology",
"pediatric hematology", etc.

To ask one's major to college students, ご専門 works, but it's better to ask
専攻【せんこう】は何ですか, because 専門 usually refers to true experts. To ask about
someone's job in general, see the answer of @IgorSkochinsky.




As mentioned in the comments, ご専門 is more about what one studies/studied. For
working people, 「お仕事は何ですか。」 should work in most cases.

If you meant to ask what a person is good at (their strong point/forte), try
「お得意{とくい}なものは何ですか。」

