Tenerife is part of the Canary Islands just like Fuerteventura is, so they speak Spanish there, too. But because Tenerife is a bigger island, there is a larger tourist population. That means that more people speak English on Tenerife than on Fuerteventura.
Fuerteventura, I noticed, also seems to have a larger population of African immigrants. I heard much less Arabic around Santa Cruz de Tenerife than I do when I'm out walking in Puerto del Rosario (my city on Fuerteventura).
They use the euro inTenerife, although everything is a little bit more expensive in the city, just like it is when you compare prices in a city and a small town in the United States.
I spent about a euro when I bought a bottle of water.
After the race, a friend and I went out to a vegan fast food restaurant. I had a lentil burger and fries, plus a piece of carrot cake to celebrate not having to diet anymore!
On the flight over, I listened to English music--Billie Eilish. But other than that one flight, I mostly listened to Maluma.