[@ArkmageddonCat] If you're using chrome: right click and translate to English. Not sure if the same is true for Firefox or the like.

The site itself can be viewed in English and some of the search tags have been romanized or translated in English in addition to their regular spelling, but in the end, due to the fact that Pixiv is an Asian site (primarily Japanese), most posts will be in some Asian language due to where the site is hosted. I've seen Europeans and other foreigners post on there, but they're a minority so it is best to translate something into Japanese and search it rather than the English spelling.