Solution : https://service.sap.com/sap/support/notes/908207 (SAP Service marketplace login required)
Key words : 
terms bas_settingsbas_aleradntlangspumgdd03l-languflag reason, support package mentioned, system mistakenly handled, unicode system, unicode systems, mdmp systems, incorrect conversion, individual entries, table t005, country table
Related Notes : 
       
| 916547 | Problems with language fields in MDMP R/3 backend systems | 
| 672835 | Textflags could cause problems during Unicode conversion | 
| 480671 | The Text Language Flag of LANG Fields |