To find background information on cross-cultural communication you will use:
The Communication textbook is the best source to find background information.
To find how many people live in Queensland, where English is not their first language you will use:
The Australian Bureau of Statistics is the best source to find demographic information.
To understand the meaning of a word you will use:
The Dictionary is the best source to find definitions of a word, but the Thesaurus and Encyclopaedia may also be useful to understand that word in context.