The main language spoken in all the cities I visited (except San Andrés) is Spanish. On the island of San Andrés, the main language is San Andrés Creole.
The Colombian Peso is the official currency of Colombia. Colombian currency is inflated compared to United States currency. To give you an idea of just how inflated: One US dollar is equivalent to approximately four thousand Colombian pesos! For reference, four thousand Colombian pesos can buy you a cup of coffee (or even two, depending on which cafe you're at) in Sogamoso.
A bottle of water in Sogamoso is typically dos mil, which is equivalent to approximately fifty cents in the United States.
After eight months in Colombia, I finally tried pollo con champiñones (chicken with mushrooms), which is a delicacy here. I tried a plate in Salento, and it was absolutely delicious! I had it alongside a limonada de coco (coconut lemonade) which is my personal favorite beverage in Colombia. It's lime juice mixed with cream of coconut and is typically served with coconut shavings--it's absolutely heavenly!