Hi, this link is dead : https://play.google.com/store/apps/details?id=org.documentfoundation.libreoffice
Where can I download Libreoffice for android ?
Nowhere. There is no such thing as LibreOffice for Android (a viewer can be downloaded from F-Droid). You might try AndrOpen Office, but it is a project not related directly to LibreOffice.
Just tested Collabora Office (downloaded 5 minutes ago from Play Market, thus, should be the latest release) with a document containing mixed scripts (Latin/Cyrillic/Chinese). It shows crossed squares instead of Chinese, while AndrOpen Office opens the document fine on the same device. Thus, Collabora Office does not seem to be a good choice, but you have to test it.
My pleasure! Point me to your bug tracker 
Point me to your bug tracker
as per play store: https://www.collaboraoffice.com/apps/ab-bug (don’t be surprised to be redirected to …)
I am surprised and confused. There is no option for Collabora Office in the product list. Should I specify Android editor or what? Mike?
@gabix: I’m sorry to not seeing the comments. The broken notification system here makes me nuts! That just doesn’t let me know someone commented something. Sorry! (I learned that all edits get as notification though; that’s why now I edit my comments immediately after posting them - so the notification of my comments gets to people.)
And indeed, you did everything right - thank you!
If you’re looking for a more lightweight and offline-capable alternative I’d recommend to give OpenDocument Reader a try: https://play.google.com/store/apps/details?id=at.tomtasche.reader
The formatting is far from perfect, but the app is a tenth of the size of other LibreOffice apps.