Hi there
Beth has explained it wonderfully - I'll just add some more information that you may or may not need.
For the first year at least, you get a designated 'language timeslot'. This means, if you study a language, you should pick that timeslot for it if possible. You get to choose your timeslots at the start at a first-come-first-served basis online, so try and pick as quickly as possible! This means that students who don't study languages usually have those 2 hours off (language classes are 2 hours long, once a week, unless you do it to count towards your degree, in which case you have an extra hour somewhere in the week).
In the second semester of the first year, 1 hour of the 2 clashed with another one of my lectures! The same thing happened in the first semester of Year 2, but I went to languages as I felt that it was more important and caught up with study some other time. This doesn't mean that it'd happen to you - I'm sure the timetabling people don't do it on purpose!
And just some more information about the course - if you do it optionally ('3 credit'
then you sit a reading, listening, writing, and speaking test in weeks 6, 7, 8, 9. (One a week) and this shows up on your degree transcript but doesn't count towards degree. You can sign up as 'attendance only' which means you don't have to sit the tests if you don't want to and it doesn't show up on your transcript, which means you're doing it out of interest. Then there's '6 credit', that some students can do, and that counts towards your degree. On top of the 4 tests that people usually do, you sit an exam in the main exam periods.