UN MIEDO (versión de Clark Coolidge)

A veces las palabras dejan de significar
lo que obligatoriamente significan para otros para mí.
¿Es que las he cambiado para que su
significado sólo lo sepa yo
y no obstante no lo sé?

[Sometimes the words will not mean
what they must mean to others to me.
Have I changed them so their
meaning only I will know
and yet do not?]

There are two syntactic hiccups [that's the technical term, I believe] I've tried to preserve in my translation. A more natural word order would be "Sometimes the words will not mean to me what they must mean to others." The second hiccup is in the last line. There seems to be a change of verbal mood between "will know" and "do not." I've switched in Spanish from indicative to subjunctive, which implies that this part of the sentence is no longer subordinate to the phrase "Have I changed them so that..."