create JSON inside SQL Server 2012 column fulltext

Not really sure what you mean by creating json in a database,

you can 100% store it, but for creating it, i suppose you could have a stored procedure where you input parameters and it would then process them and write a json result to a column in a row in a table, then you could read the result from where ever you stored it. does that work for you?

as for supporting multiple languages? you can absolutely create a database that stores your entities in multiple languages it'll just be a pain in the ass to do, you really have to be careful how you design it, and there really isn't a magical bullet.

here's a good article
http://www.codeproject.com/Articles/752301/Multilanguage-Database-Design-in-MySQL

what i would do is design my database as normally in my language of preference, but move all the Display data (product names, descriptions, anything that a user will read) into foreign tables, then in those display tables i would have a compound primary key made up of the language code and the foreign key referencing your original data I've attached a very basic image of what i mean

my advice is research different approaches look at your data, and the size of your project then decide what works best for you.
Languge-desgin.png