I don't think it should be mandatory, but in my case it was.. you had a choice between Spanish, French, German, Italian or Sign..
I ended up taking Spanish in high school, because I had it in junior high and it was really fun and I excelled at it. So for me it was a natural fit, although I wish we could have chosen multiples, because I would have tried to learn the others too.. especially sign. I would love to learn Japanese, Korean and Chinese, but I would have to learn their alphabet first, like the others amd also learn how to write them properly.. so thst I don't accidently say the wrong thing or insult someone.
But I loved Spanish, and it has come in handy outside of school, not just at work, but in daily life. The looks I get when I walk into a restaurant and start speaking Spanish is interesting.. I don't do this for all Spanish businesses, just in places that don't have signage in English.. and I have gotten looks from shock to appreciation. At work, I have found that when you speak their language, they tend to trust you more. When I worked at a theatre, my boss told us to automatically sell large everything to anyone who didn't speak English.. since, this was in Queens, and he spoke Chinese and Korean natively, this left only Spanish.
So I would take orders for the people on my line, but whenever I got someone who looked confused, and had nervous or unsure body language, the first thing I asked them was if they spoke Spanish.. in their language.. they immediately smiled and nodded and I took their entire order in Spanish.. I needed the practice since I hadn't spoken it much outside of school and it didn't sit right with me to automatically charge someone who didn't know the language for large everything. Anyway, after I took their order and we had a light conversation while doing so, I didn't think much of it, and moved on to the next customer..
The next thing I know, my boss, the same boss I mentioned earlier, asks me to speak with him in his office as soon as I came in. I am barely into his office doorway when he asks me what it was that I did when I worked my last shift.. and I asked him what he meant.. he said that people a lot of people had been coming in for that past 3 days asking for me specifically and said that the family who I served on my last shift, left me a big tip.. and the first thing I did was apologize, since we aren't allowed to take tips unless it was for charity and I told him that I had no idea that it was going happen and that I only took their order in their language because it didn't feel right to automatically charge them for a large everything like he said to.
After that, he told me that he would like me to be the one to deal with the Spanish speaking customers because he had always had trouble with it himself, and it was for that reason he stuck with Chinese and Korean since those were the languages he heard growing up. And I agreed to so.
But that wasn't the only reason he called me into the office, he also said that I made so much money on my register, that he at the end of the night, when he counted it, he thought there was a mistake, but then after looking at the security footage from above my register, he found out that the same family I took care of left me a tip at customer service and said that although tipping was not their policy, and they dont allow people to ask for them, or have a non-charity tip jar that he would make an exception in my case, and allow me to keep my tips and said that he instructed customer service to hold on to any tips that came in for me and to give them to me at the end of the night before leaving.
So I would say that knowing Spanish was very useful and it allowed me to make more money, just by speaking it. And it is very useful when traveling because there are some places that don't speak English, but they also speak Spanish as their second language because it is easier, and so, Spanish is often a second option that many don't know. Even the Chinese people here have Spanish as their second language now instead of English, and I am not sure when that changed, but it wasnt the case when I was in high school.