How to control the language of the paypal checkout page?

Question

I am using perstashop (an open source Eshop framework) paypal plugin to implement the paypal function.

Actually it is the PHP framework so it should be similar to other site implementation.

I would like to change the language of checkout page

And here is the code:

<form id="paypal_payment_form" action="{$base_dir_ssl}modules/paypal/express_checkout/payment.php" data-ajax="false" title="{l s='Pay with PayPal' mod='paypal'}" method="post">
    <input type="hidden" name="express_checkout" value="{$PayPal_payment_type|escape:'htmlall':'UTF-8'}"/>
    <input type="hidden" name="current_shop_url" value="{$PayPal_current_page|escape:'htmlall':'UTF-8'}" />
    <input type="hidden" name="bn" value="{$PayPal_tracking_code|escape:'htmlall':'UTF-8'}" />
</form>  

Someone said put the line

<input type="hidden" name="lc" value="xx_XX">

in the form, I check the support locale code list and put it , unluckly it remain the same

So I wonder:

1) is this correct or I need to change elsewhere?

2) is the language in paypal changed in paypal panel instead of code? there is a default language setting, but how can I dynamic change base on the Eshop language?

3) can I control the language choice as well? My eshop has English, France and Germany but paypal checkout can only change between English and France, any idea ?

It is classic express checkout page.

Thanks for helping.

Update:

Found that the language is control by the delivery address. Then it means I can somehow change that

Answer 1

I offered some time ago a bounty for the same thing. Nobody was able to help me: paypal express checkout: 2 language

From what I figured the language depended on the country where the delivery was going to + if the person had an account with paypal and the language they previously used.