Problems using multi-lexer in 8.1.7

Question

Hello,
Have a UTF8 database and have created a
table to hold multi-language data.
Created an intermedia index using multi-lexer . Have problems quering data out of the table ; specifically the last 2 queries.
Any ideas?
SQL> exec ctxsys.ctx_ddl.create_preference('aenglish_lexer','basic_lexer');
PL/SQL procedure successfully completed.
SQL> exec ctxsys.ctx_ddl.set_attribute('aenglish_lexer','index_themes','YES');
PL/SQL procedure successfully completed.
SQL> exec ctxsys.ctx_ddl.set_attribute('aenglish_lexer','theme_language','english');
PL/SQL procedure successfully completed.
SQL> exec ctxsys.ctx_ddl.set_attribute('aenglish_lexer','mixed_case','YES');
PL/SQL procedure successfully completed.
SQL> exec ctxsys.ctx_ddl.create_preference('agerman_lexer','basic_lexer');
PL/SQL procedure successfully completed.
SQL> exec ctxsys.ctx_ddl.set_attribute('agerman_lexer','mixed_case','YES');
PL/SQL procedure successfully completed.
SQL> exec ctxsys.ctx_ddl.create_preference('afrench_lexer','basic_lexer');
PL/SQL procedure successfully completed.
SQL> exec ctxsys.ctx_ddl.set_attribute('afrench_lexer','mixed_case','YES');
PL/SQL procedure successfully completed.
SQL> execute ctx_ddl.create_preference('aglobal_lexer','MULTI_LEXER');
PL/SQL procedure successfully completed.
SQL>
SQL> begin
2 ctx_ddl.add_sub_lexer('aglobal_lexer', 'default','aenglish_lexer');
3 ctx_ddl.add_sub_lexer('aglobal_lexer', 'german', 'agerman_lexer','ger');
4 ctx_ddl.add_sub_lexer('aglobal_lexer', 'french', 'afrench_lexer','frn');
5 end;
6 /
PL/SQL procedure successfully completed.
SQL> create table adam (
2 doc_id number primary key,
3 lang varchar2(10),
4 text varchar2(100)
5 );
Table created.
SQL>
SQL>
SQL> insert into adam values (1, 'german', 'Ich ging Berlim. ');
1 row created.
SQL> insert into adam values (2, 'french', 'Je suis alli a Paris. ');
1 row created.
SQL> insert into adam values (3, 'english', 'I went to London. ');
1 row created.
SQL> commit;
Commit complete.
SQL> create index globalx on adam(text)
2 indextype is ctxsys.context
3 parameters ('lexer aglobal_lexer
4 language column LANG'
5 );
Index created.
SQL> col text format A50
SQL> --
SQL> -- QUERIES :
SQL> --
SQL> -- These are the following 3 rows in the table :
SQL> -- (1, 'german', 'Ich ging Berlim. ')
SQL> -- (2, 'french', 'Je suis alli a Paris. ')
SQL> -- (3, 'english', 'I went to London. ')
SQL> --
SQL> alter session set nls_language=AMERICAN;
Session altered.
SQL> alter session set nls_territory=AMERICA;
Session altered.
SQL> select doc_id, text from adam
2 where contains(text, 'London') > 0;
DOC_ID TEXT
3 I went to London.
SQL> --
SQL> -- SHOULD NOT return French data!
SQL> --
SQL> select doc_id, text from adam
2 where contains(text, 'alli') > 0;
DOC_ID TEXT
2 Je suis alli a Paris.
SQL> alter session set nls_language=GERMAN;
Session altered.
SQL> alter session set nls_territory=GERMANY;
Session altered.
SQL> --
SQL> -- SHOULD NOT return ENGLISH data! Also does not return valid GERMAN data
SQL> --
SQL> select doc_id, text from adam
2 where contains(text, 'I') > 0;
DOC_ID TEXT
3 I went to London.
null

Answer 1

First of all in your aenglish_lexer, index_themes should be 'false'.
The attribute 'alternate_spelling' for German should help. Please read the documentation for examples.