disable default English autocorrect

Hello,

I constantly try to use Zoho Writer instead of LibreOffice.
This is probably the first case when I can't figure out or stand a little problem with this.
Maybe solution is simply but I can't find it.

I often need to use word "i" in my language, and I have no idea how can I turn off auto correction this word to uppercase English "I". Autocorrect is turned off, turn off spell checking and change language to another also doesn't help.

Please help because I don't want to must return to every "I" and manually repair it...

Thanks in advance
Eve