I copied the lyrics with the chords from there. The language is indeed Catalan and the closest language to it is Occitan. The song was written in 1974, i.e. before Franco died, which probably tells much: he'd be censored and victim of intellectual harrassment; he left Catalonia from 1971 to 1976 for an exile in Paris he called "tourism for political motivations". Those who know Spanish or French, the Wiki entry is much longer and more documented, of course the Catalan entry is the longuest and most documented.

Here is my (literal) try

If you must hush me/make me hush,
Let it be now,
Now that than I can say no
And [that] you have nothing to buy/bribe me.

I don't want to wait:
Let it be now!
Now that I can feel
The weight of such dread.

It doesn't hurt me
To have my mouth shut,
You're the ones who have turned
The silence into words (who've made words from silence).

I don't want to wait
For time to rust the (my) soul,
I don't want fear
To have more time to overwhelm me;

If you must hush me/make me hush,
Let it be now,
Now that I have my hands
[busy with] changing my guitar.