One of the things I wanted from my time in South America was to learn a little Spanish, where to give me a start I used a language school. I'd wanted to use some of my time in Central Asia to learn the basics of Spanish, but that was wildly optimistic - with overlanding all you can focus on is what is there, which is part of the joy.
There are many different schools across all of South America (it is common for travellers to try and learn a little of the language - if nothing else in some countries you need to have some Spanish (Bolivia, for example) as otherwise you won't get around) and I used FairPlay in Cusco, based on a recommendation from Gil who had also used them.
FairPlay isn't just a language school, it's also an NGO which helps locals. In its own words:
FairPlay is a not-for-profit organisation that was founded in September 2006 and helps disadvantaged people in Cusco build stable, prosperous futures for themselves. We provide high quality services to travelers and volunteers, including Spanish tuition, facilitating volunteer placements and homestays, while helping local people to help themselves.We do this by offering free and comprehensive training through our NGO to determined, talented Cusceneans who could not otherwise afford the education they need to get a properly paid job.We then provide these people with employment so that they can put their new skills to use and earn a living wage for themselves and their families. These previously marginalized people earn money, but they also earn the respect of their communities and a new place in society.(Source: http://www.fairplay-peru.org/en/Volunteers/Live__Learn/The_FairPlay_Idea/)
I really like that in learning something and do something which benefits me, I am doing something which benefits those who live where I am visiting.
The teaching itself is in Spanish, where learning a language being taught in that language (where you don't speak that language) is interesting. It is made more interesting in that my teacher didn't speak English, but that is part of the immersive experience - it is hard work (very hard work in places, leaving me feel like I'd done a few rounds with Tyson), but it works.
I originally booked 2 weeks of lessons (4 hours a day, 2 of grammar and 2 of practical), but this turned into 3 - in part as I was making (slow and painful) progress and didn't want to stop and in part because I'd got the time (see passport saga for details).
It took me 3 weeks to do most of what should have taken 2, where this is no reflection on the school or teachers, but simply my ability to learn languages. For as easy as I find it to learn technology, I find it hard to learn languages.
The school left me with enough Spanish (language and confidence to use the language) to mostly get-by in Spanish for the rest of my time in South America, as long as people spoke slowly (different countries within South America speak at very different speeds - Peru, especially in Cusco, have a nice and slow place - not so in Chile, for example) and didn't want to discuss anything complex.
It may not sound like much, but being able to go to the bus station in La Paz, discuss what you need and buy a ticket in fluent enough Spanish is a great feeling, especially when you arrived in the country with essentially no Spanish.
The school works well with those who arrive with some Spanish (Rosie, a fellow inhabitant at Mama Carmen's, arrived with A-level Spanish and was off to (and is now at) Cambridge to study languages - not a beginner by any measure) and can cater lessons to your needs. Working within their volunteering program is another great way to learn, if you've got the wherewithal to work with kids - I don't.
The social side of the school - salsa lessons (yes, I tried; yes, I have two left feet; yes, I really enjoyed it) and the cooking lessons - makes for a very friendly atmosphere (I've stayed in hostels with worse atmospheres) and a nice vibe to the place.
The home-stays are great - it is the chance to live with locals for a while, eat proper Peruvian food (which I lucked-out on, as Mama Carmen is a brilliant cook), use the language and see a side of Cusco beyond the hostel & the usual sites. Again, in doing this you help others and you help yourself. It also gave me something I'd not had for a long time - the chance to be static.
I struggled to learn any more Spanish after leaving the school, which in part was due to being surround by English everywhere I went in South America (it is the defacto language in every hostel) and in part through laziness - none of us like studying what we know we are bad at / struggle with.
Many months later and I'm back in London and I still have some of what I was taught in the school - I recently went to a Bomba Estereo gig and was able to talk a little with the ticket staff in Spanish and understand a few of the lyrics.
If you are looking to study Spanish whilst in Peru I highly recommend FairPlay - it is a good school and they do good.