What UCB said. For Algorithms alone I used two different languages depending on what the problem needed. Once you know a few languages, you should be able to learn the others: PL should help you decide what languages are best for what task.
Best of luck! Your final year will be very intense. Your upcoming one seems manageable enough: if you find that to be anything but at the very least “relatively easy”, switch to my suggested summer plan or another more relaxed plan. I’m still a bit wary about all those classes being 3 credits. Hard work doesn’t always make the difference.