That depends on which field are you using on LSMW I guess you are using ADDRESS-ADDRESSES-DATA-COMMUNICATION-POSTAL-DATA-LANGU in this case for spain is 'S' as I already said, you can check that on the table T002. if you are using ADDRESS-ADDRESSES-DATA-COMMUNICATION-POSTAL-DATA-LANGUISO should be 'ES'. In other hand don't forget to also inform the X fields
ADDRESS-ADDRESSES-DATA-COMMUNICATION-POSTAL-DATAX-LANGU
OR
ADDRESS-ADDRESSES-DATA-COMMUNICATION-POSTAL-DATAX-LANGUISO
Depending which field are you informing on the DATA segment.Otherwise the value will be never updated!