How can I set different html lang attribute for different countries?

My WordPress theme header.php html language attitude

!DOCTYPE html
html ?php language_attributes(); ?

All page html language attitude :

html lang=en-US

But I have some pages for different countries. I want to use different html lang attitude code for each country page with single header.php

For example:

English page language attitude : html lang=en

Portuguese page language attitude : html lang=pt

Spanish page language attitude : html lang=es

Indonesian page language attitude : html lang=id

Vietnamese page language attitude : html lang=vi

etc...

How can I do it?