I studied languages at UCL 10 years ago so things may have changed by now. At the time, they had a very diverse range of languages to choose from, from romance languages to Slavonic to Nordic to Germanic etc. This opened up many doors and students had the chance to pick up a new language from scratch. There were language modules and modules on culture. However, the more popular languages seemed to have a much wider range of modules to choose from compared to the less popular ones. Teaching quality was mixed- I had both good and bad experience.
UCL is a very international uni with many students from outside the UK, which is really fun! Being in London, students have so much at their disposal in terms of entertainment, night life and leisure- you definitely won’t get bored! However, UCL is not a campus uni so you don’t get the same community feel as you might do elsewhere- this can sometimes make it hard to make friends. London also makes student life expensive.