When I was a student, our English teacher from the US used to correct us when we complained about too many 'unknown words' in texts. He told us that it was better to say 'new words'. Now that I've begun preparing for my exams, I sometimes come across that 'unknown words' collocation in books and on the Internet. Is that just a matter of taste?
Thank you in advance.
I suppose your teacher had the idea that the words were not 'new'; they had been in use for a long time. So, he preferred you to say 'unknown'. I suppose if one wanted to be fussy, one should say 'new to me' or 'unknown to me', but most people are happy enough with just 'new' or 'unknown'