do people in that region speaks cantonese?
Yes, around 0.8%.
Western Australia
 Cantonese (0.8%) 
what is the location of "forrest highway"? It is located in Western Australia's Peel and South West regions. what languages are spoken in the former region? Mostly English, along with Mandarin, Italian and Vietnamese, to name a few.
wiki:19672710
Western Australia [SEP] Language
At the 2016 census, 75.2% of inhabitants spoke only English at home, with the next most common languages being Mandarin (1.9%), Italian (1.2%), Vietnamese (0.8%), Cantonese (0.8%) and Tagalog (0.6%).