In one particular dream a woman was speaking to me in Spanish, which is a language I don't know. I knew it was Spanish and I could tell she was very distressed but seriously, my dream needed subtitles.
Several years ago, I dreamed a man was sitting on my bed and speaking to me. It seemed important because he repeated himself several times, quite emphatically. I woke and phonetically wrote what he said down so I could make sense (or no sense) of it the next morning. After doing a search I figured out it was Gaelic. Even more perplexing was that the sentence actually made sense and ended up being very helpful in what I was writing at the time.
So why does this happen? It could be that I've heard the language before and it got stored in my brain. Or it could be that our brains are far more complex than we think.
My husband was watching a movie several months ago. I was in the kitchen and busy with something else. Half-listening, I heard and understood what was being said...until I realized they were speaking a different language and then, I didn't. It was like I had it for a split second and once my brain adjusted itself, it was gone. The movie was a Welsh Indie with subtitles. I asked my husband if the actors had switched to English at some point and he said they hadn't. Which left me with a big ??
So here's my idea: maybe our brains have the capacity to comprehend all sorts of languages, regardless if we've studied them or not. Maybe somewhere deep inside all the languages are there--like stubborn, inaccessible folders.
But again, maybe this is one of those unexplained things.