Language switch in "productdetail" does not work

[axone]

Hello, 

I'm turning around for several days on a language change problem on Joomla 3.4.3 and VirtueMart 3.0.9. The site displays the languages flags and both menus are configured correctly. The site is fully translated and works well ... except for VirtueMart. If I press category it's ok language is switched properly, but after if I press on a product, it is displayed in the base language.

Here is the URL that is displayed via the link:

index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=32&virtuemart_category_id=5

It seems clear to me that the parameter "&lang" is not passed properly. But I do not know where and how to make the change ...  Does anyone have an idea? 

Thanks for your help.

[jjk]

Recently there were also several changes in Joomla concerning language switching. So there is a chance that VM 3.0.9 doesn't work correctly with the latest Joomla version (I didn't test that, but it's a possibility). Maybe try an update to VM 3.0.9.4. I don't have any language switching problems with that version. &lang=de and &lang=en are added to the end of my urls.

[axone]

Thank you for your answer.

I tried to update with 3.9.0.4 and 3.9.0.6, but that does not correct the problem. Do you have an idea of ​​which file and where do I correct to solve this problem ?

[axone]

I found how to correct the problem , I have enabled in Joomla SEO (SELF), thanks.