Language and memory
Some memories seem to be language-specific. For example, while working in Taipei I memorised various local addresses and phone numbers in Mandarin. If you asked me for such information in another language, e.g. English, I’d have to think of it in Mandarin first, then translate in my head. Similarly I know the contact details of Radio Cymru (the Welsh language radio station) in Welsh, but would have to mentally translate them first to give you them in English.
While in Taiwan, I drifted into the wonderful world of IT. Most of the things I learnt about computers were in Mandarin. So when I returned to the UK, I had to learn some of the terminology again, but this time in English. Has anybody had similar experiences of learning something in a foreign language, then having to relearn it in their native tongue?
When languages die, is the knowledge that people have built up over countless generations lost? Some of that knowledge may be translated into the new languages people adopt, but this is not always the case.