For them to say they prefer English because it allows them to express themselves better, because it's «more flexible»... that's something I honestly don't even know how to describe. And it makes me rethink how we are teaching Spanish to our children.

Because that flexibility they feel isn't inherent to the language; it's cultural. English is perceived as freer, more modern, more direct. But that's an association, not a grammatical property or a syntactic reality when writing.

Syntactic flexibility, what you'd call syntactic flexibility, English doesn't have it. It's a language with a rigid structure—subject, verb, object—from which you can barely deviate without losing meaning. Spanish, on the other hand, allows you to move the parts of a sentence in ways that English simply doesn't permit. And what changes with that movement isn't just the order: it's the emphasis, the rhythm, the intention. To that, you have to add a morphological richness—nuances, verbs, conjugations—that English barely touches. And if the argument is that English allows nouns to be easily converted into verbs or adjectives as needed, let's not forget that Spanish does too: prefixes, suffixes, derivations that transform any noun into a verb or any verb into an adjective. The difference is that in Spanish, this ability coexists with a lexical precision that means the word you're looking for almost always already exists. There's no need to invent it.

I think that, in the end, what they call «flexibility» is nothing more than laziness for not looking for the precise word, the phrase that our language already has.