There are several ways to change locale, you can try all of them to find what works for you,

Use Args when launching

const browser = await puppeteer.launch({    headless: false,    args: ['--lang=bn-BD,bn']});

Send the language as Header

await page.setExtraHTTPHeaders({    'Accept-Language': 'bn'});

Forcefully set the language

// Set the language forcefully on javascriptawait page.evaluateOnNewDocument(() => {    Object.defineProperty(navigator, "language", {        get: function() {            return "bn-BD";        }    });    Object.defineProperty(navigator, "languages", {        get: function() {            return ["bn-BD", "bn"];        }    });});

For the sake of testing, I'll test this in multiple languages, including es, and here is the result.

Google search:

BrowserLeaks:

There's an error in Md-Abu-Taher's answer.

The response to navigator.language should return a string, not an array. Try it in your own browser console.

The code snippet should be:

await page.evaluateOnNewDocument(() => {    Object.defineProperty(navigator, "language", {        get: function() {            return "en-GB";        }    });    Object.defineProperty(navigator, "languages", {        get: function() {            return ["en-GB", "en"];        }    });});