Answer:
1. Practicar un deporte
2. Porque todo lo que uno dice tiene otra definición
3. De que no sabían nada de español
4. Porque nunca lo aprendían
Step-by-step explanation:
I can answer because I could identify the song through the questions... but next time, please add the context so we can easily identify the source.
1. ¿Cuál de las siguientes cosas no hicieron los cantantes?
In the first 30 seconds of the song, they say they have traveled to different countries (Viajar por distintos países), they knew the most beautiful women, they tried delicious food (Probar comida deliciosa) and danced to very different rhythms (Bailar ritmos muy diferentes), but they never talk about doing any sport (Practicar un deporte).
2. ¿Por qué es tan difícil hablar español para los cantantes?
Because all that one says has another definition (Porque todo lo que uno dice tiene otra definición). That's to express that even if there are many countries that speak Spanish, each country's Spanish is a bit different and shows various meanings for a same word. Later in the song, they proceed to give the examples of words that have meaning A in one country and meaning B (often the total opposite) in another.
3. ¿De qué se dieron cuenta los cantantes en su viaje a las Islas Canarias?
That they knew nothing about Spanish (De que no sabían nada de español) because they couldn't communicate with the people there correctly. They then decided to go study in Spain to improve their knowledge of Spanish, in hope to understand more Spanish-speaking people from around the world. The singers are brothers from Colombia.
4. ¿Por qué los cantantes estudiaron tanto español?
Because they say they never learned it (Porque nunca lo aprendían). That's the conclusion they drew after encountering so many issues with the vocabularies going from one country to another. That's why they say that once you learned Spanish in one country, don't move out of there... because you'll have to learn it all over again.