I was about 6 or 7 and was given a book of simple French words. I spent ages trying to work out the code which governed the translation, e.g. if hello was merci, then h=m, e=e, l=r etc. depending on where the letters were in the word. I used to make up my own languages on this basis.
I still do have too much fascination with words - I study linguistics.
A childhood belief about foreign languages

others believed things like this
- I used to wander what my name would be in other languages. I thought that names worked the same way as words. — Simon
- I used to believe that all languages were just jiberish and I asked my mom why they didn't use real words.Anon
- I used to think that birds sang in different languages depending on the country they were in!— Sarah
- I thought the word economical was actually two words: eek and omical.
— Nancy M. - I used to believe that the words Angliphile and Francophile were related to the word paedophiles.Anon
- I used to believe that all four-letter words are bad words.Anon