Hm, I'm too sure no more if the products_id is not unique... That what it seems to be when I look at the MySQL data with the 'Sequel Pro' app. When I look at the data linked with the ActualTech ODBC driver, I see unique products ID's. I don't get it why Sequel Pro let's me see two products_id's, along with two language_id's. Perhaps Sequel Pro sees the relationship and shows me the according records??
Perhaps you have more than one table and they are linked by Products_ID?
In one table, you have one record per product and Products_ID would then be the primary key. In the other table you have different transalations of the various product descriptions. In that table, Products_ID is the foreign key.