Change form field title's dynamically

I am trying to change variable value from another page.

For example:

 In form.dart I have created form , then I have another pages with name english.dart,Hindi.dart ,Tamil.dart In these pages I am declaring variable value.

I want to set those values from those pages when I choose that language.

changing value working fine ,If I have declare those value in same page and call inside seState but how to set variable value from another page as my form length is too long and I need it in different languages that's why I need to call it from another file.

Thanks in advance for help.