The referendum that is to be held in 1-O is about much more than language, cultural identity or economics: it is currently about defending the civil rights of the country and the ability of catalans to be able to freely decide their own future, exactly as it happened in other more democratic countries such as Canada or the UK.
But it isn't. It would be, if it were done legally, with general support, completely in the open, with fair campaigning for both sides, and with central support (which is what happened in the UK). But 1-O isn't a fair expression of the Catalan people's right to self-determination. That's just a thin veil based on a fair, but right now unattainable, ideal. What is really going on under the hood is basically an illegitimate power-grab by the pro-independence parties. Running a "democratic" process that is single-handedly controlled and promoted by those with an interest in a single outcome isn't democracy, it's the hallmark of authoritarian regimes, because the outcome will inevitably be what they want (as those who disagree will have a much lower participation in the poll than those who agree).
Yes, this is tough for the Catalan people, because they have not been given a fair chance to express their will yet, but this isn't it by any stretch of the imagination. 1-O isn't about self-determination, it's a bullshit political move that rises up to the political bullshit standard of the central government (which is legendarily full of it too).