Actually, browsers do change behavior because of it[1], and users do get affected by it[2]. Google have said last year they ignore the lang tag but they do use

Actually, browsers do change behavior because of it[1], and users do get affected by it[2]. Google have said last year they ignore the lang tag but they do use the hreflang attribute[3] [1] https://www.w3.org/International/tests/repo/results/the-lang-attribute#basics https://www.w3.org/International/tests/repo/results/the-lang... [2] http://accessibility.psu.edu/foreignlanguages/langtaghtml/#about http://accessibility.psu.edu/foreignlanguages/langtaghtml/#a... [3] https://www.seroundtable.com/google-ignores-the-html-lang-attribute-22974.html https://www.seroundtable.com/google-ignores-the-html-lang-at...