I’ve tried to reword the question to what OP Sam Rizzardi intended (“what do King James Only proponents think…”); but QCR knows what he intended out of the question better than OP does, clearly. *sigh*
There are different flavours of King James Only, as explained at King James Only movement – Wikipedia. Not all versions hold that KJV is divinely inspired, and most are opposed to modern textual scholarship (moving away from the Textus Receptus for the Greek); they would find allies in the Greek Orthodox church. In most versions, KJO says nothing about languages outside of English.
Going through the flavours.
- “I Like the KJV Best”. Likes it for style, doesn’t actually make any big theological claims. Indifferent to other languages.
- “The Textual Argument”. Prefers the older redactions of the Greek and Hebrew texts that the KJV used. Would be fine with e.g. the Vulgate for the same reason.
- “Received Text Only”. Thinks the older redactions of the Greek and Hebrew texts are providentially selected. Again, would be fine with e.g. the Vulgate for the same reason.
- “The Inspired KJV Group”. Holds that the KJV translation itself was divinely inspired. Does not necessarily say that translations into other languages might not be divinely inspired; though I assume they don’t expend a lot of energy exploring that possibility.
- “The KJV As New Revelation”. Holds that the KJV translation supersedes the original Greek and Hebrew themselves, because it is literally a new revelation from God. Would therefore reject all other translations, unless they are translations from the KJV direct. Called Ruckmanism after Peter Ruckman.
Where does it leave non-English translations? #1 doesn’t care. #2–#3 wants them to be textually conservative. #4 is agnostic about them (though it would at minimum expect them to be textually conservative as well). #5 rejects them.