A couple of days back, I had a very strange dream that was very nostalgic and pleasant with an overarching fear of going back to the present.

In the dream I was back in my birthplace, Hong Kong in the past, with my grandmother who lived in Shenzhen at the time.

I was a child and my grandmother spoke fluent Shanghainese to me, whilst I was replying in fluent Cantonese. But when I woke up I remembered that I can't fluently speak either of those languages... I can understand about 80% of Shanghainese and about 10-20% of Cantonese.

The conclusion I came to was that I was probably, in my dream, making random noises that sounded like those languages: "wuu zii ghuyuen ngyuuu ckhuu" "bin guk tsing tong yuk gak gai laa" XD

But the point is, I have heard of people subconsciously knowing a language and having it come out during dreams. XD The subconscious is a strange place indeed.

Subconscious has an incredible memory. It will happen that you only heard a language once and what you've heard will stay engraved somewhere in your mind. If you don't use it a lot, you will tend to forget you actually know it, but the subconscious will remember it.

Subconscious will remember everything from the day you were born (even further like you as a foetus or even a past life) until the day you are currently living. Some people with emotional problems can go to get a hypnose to get back in time (regressions) to find the source of the problem and then work for a solution.

Your subconscious knows everything and once it's unlocked, possibilities are unlimited