Possible Clues:

• Preserve intonational variations with East Asian language
• Canadian accent's associated with oriental language
• Tongue with six phonetic tones
• Some intoxicant one serves with a particular kind of Chinese food
• Macau characters
• Accents grasped by staff in Asian language
• Staff enlisting characters from the Far East
• Language modulations adopted by staff
• Language whose name aptly contains the word 'tones'
• Like dim sum