knowledge base, the 2 ways, questions

I've read there are 2 ways to add my custom thesaurus in the Oracle Text: (1) use my custom thesaurus and use the thesaurus operators or (2) augment my knowledge base with my custom thesaurus.

Questions:
- in the first way Can I make the THEMES queries or the ABOUT queries ?

• in the second way am I limited to the english language ?