Learn Spanish (Latin America): Siempre me pregunto por qué caminan tan apresurados. - I always wonder why they walk so hurriedly.

Instead of using me pregunto (I wonder), you can use the future tense to express a guess or wonder about the present. You would drop me pregunto and change the main verb to the future tense: ¿Por qué caminarán tan apresurados? (Why might they be walking / I wonder why they walk so hurriedly?). Both ways are very common!

Why is it me pregunto and not just pregunto?

The verb preguntar means to ask someone else a question. When you use it reflexively as preguntarse (by adding me, te, se, etc.), it literally means to ask oneself. In English, we naturally translate this as to wonder.

Why is apresurados plural? Doesn't it translate to the adverb "hurriedly"?

While English uses the adverb hurriedly, Spanish often uses an adjective to describe how someone performs an action, especially with verbs of motion like caminar. Because apresurados acts as an adjective here, it must agree with the subject. It is masculine and plural to match the implied they (ellos) who are walking.

Why do we use tan here instead of tanto?