A visitor from Germany lands on your English domain. They may have no idea that the same page also exists in German, on another domain.

Switch on Language suggestion and a small bar appears at the bottom of the page. It offers that page in the language their browser asks for. It never moves anybody by itself. It only offers.

What the visitor sees

A bar at the bottom of the page, written in their own language. One sentence, a link to the same page on that language's domain, and a close button.

The bar floats over the page instead of pushing it down, so nothing jumps around while the page loads.

When someone closes the bar, that choice is saved in a cookie on that domain for 30 days, for that language. They are not asked about that language again. The choice does not travel to your other domains, because a cookie always belongs to one domain.

When the bar shows up

Only when all of this is true:

• the setting is on and the visitor is on a domain you configured;
• the page also exists in another language on another domain, and the two pages are linked to each other in Joomla;
• the first language the browser asks for is not the language of the page;
• the visitor did not close the bar for that language in the last 30 days.

An exact match beats a general one. A browser that asks for nl-BE gets the Belgian page if you have one, and the Dutch page if you do not.

Does the bar never show up? Troubleshooting walks through the causes one by one.

What it needs

The suggestion reads the hreflang links in the page. Those are the tags that say which page is the same page in another language. So in the System - Language Filter plugin, Add Alternate Meta Tags has to be on. It is on by default.

A page that is not linked to a page in another language gets no bar. That is the honest outcome: there is nothing to link to.

Page cache and privacy

Every visitor gets exactly the same page. The page carries all the possible suggestions, and the choice is made in the browser.

That keeps Joomla's page cache working, and it means nobody is profiled on your server. Nothing is stored except that one cookie, and only when a visitor closes the bar.

Changing how it looks

The bar uses the class dpl-suggest, with a link and a button inside it. The built-in styling is deliberately weak, so a rule in your own template stylesheet wins:

.dpl-suggest { background: #003366; font-size: 1.1rem; }
.dpl-suggest a { color: #ffd700; }