What about fourth solution?
[ products ]
id (INT)
language (VARCHAR 2)
name (VARCHAR)
description (VARCHAR)
price (DECIMAL)
*translation_of (INT FK)*
*Translation_of* is FK of it self. When You add default language *translation_of* is set to Null. But when you add second language *translation_of* takes primary produkt language id.
SELECT * FROM products WHERE id = 1 AND translation_of = 1
In that case we get all translations for product with id is 1.
SELECT * FROM products WHERE id = 1 AND translation_of = 1 AND language = 'pl'
We get only product in Polish translation. Without second table and JOINS.
