I can only answer for the UK, but no. You can choose to learn Arabic, but it isn't mandatory. Student's in the UK must learn a language but it is usually a European language, French, Italian, German or Spanish being the most popular. Some ethnic minority students study languages they speak, such as Gujurati, Arabic or Hindi, but this is rarely offered by the school and would usually only be offered in schools with a large ethnic minority student population. However the student is free to learn any language they choose in their own time and I had lots of friends that learned Arabic either through family or through the mosque.