The default language for SQL Login is English, if you would like change it to your own country's language, please follow the steps below to adjust it.
1. Login to your database with sql server management studio
2. Run query 
ALTER LOGIN [SQL Login] WITH DEFAULT_LANGUAGE = your language
 
Note: 
1. replace  "
[SQL Login]"  with your database login name. 
2. The Database Engine contains the following installed languages: 
here
e.g. change to French
ALTER LOGIN DB_9B091A_demo_admin WITH DEFAULT_LANGUAGE = French
 Article ID: 1440, Created: May 22, 2013 at 2:45 AM, Modified: July 25, 2014 at 12:30 AM