If your website is in one language, there is no obligation to provide more than one language (assuming that your website isn't an official government website, in which case every language used by that government should be provided).
If the content on your website created by you is in multiple languages, better practice would be to have policies in each of those languages, and a Google translate widget would certainly be appreciated by users and would reduce misunderstandings.
If you have more than one language you should state that one of them (in your case, probably the Spanish one) should be considered authoritative if there is a conflict in translation or meaning between them in every version that you provide.
The basic legal question is whether you have sufficiently put people on notice of what the legal pages say for it to be possible for a diligent reasonable user of the website to locate them and read them.
You might also consider having a prominent page or window that has to be clicked upon with a one line statement in every possible language that says: "The legal pages of this website are available in the Spanish language at this link." Then, someone who didn't speak Spanish couldn't complain that they didn't know where to look for the legal pages so that they could translate and read them.
This might be particularly important if one or more the languages used by your website users doesn't use the roman script. For example, someone who was literate in Korean or Chinese or Bengali might not be able to look at a statement in Spanish and have any idea that it is talking about legal pages, any more than you could look at a bunch of Chinese characters and figure out what it was trying to say without great difficulty.