Hi, Your menu is too wide, and in general there no space for extra module.

I see those options:

1. Remove Search icon and publish Language Module in "Menu" position. Or the same position as you have "Search" icon now.
2. Logo column reduce size from 2 to 1. And add extra +1 to menu column. I mean, change header grid. Then will be more space for extra module in "menu" position.
3. Use Sticky Module and publish Language flag module at the right or left screen side.
4. Make header a wider, not in default container like you have now, and there will be more space for extra modules in desktop and laptop view. Example:

@media screen and (min-width: 1360px) {
#sp-header > .container {max-width: 1320px;}
}
@media screen and (min-width: 1240px) {
#sp-header > .container {max-width: 1220px;}
}
#sp-menu {padding-left: 0;}

Probably, there are other ideas; as an experienced webmaster, think out the box.

HI Thank you for the quick response. I set the language change to "menu" and removed a menu link. Strangely, it appears in the top left corner. I like the solution [2] by giving more space to the menu, but without Helix, I don't see how to do it. Regards

But as webmaster you know how to use "order:1 , order:2", hmm? If not yet...

#sp-menu > .sp-column {display: inline-flex;}
#sp-menu > .sp-column > .sp-module {order: 2; margin-left: 20px;margin-top: 25px;}

Okay, thanks, yes, I know to use "order:1 ...". I thought it was in the template: layout builder , but the main menu is in the [offcancas] position. i see

After using my CSS - language module should be on the right side of menu. Whole rest is on your hands.

I gave you tips. C'est à vous de décider de l'usage que vous en ferez.