Do you think a person, not fluent in speaking English, fit for front office?

Difenetly my answer is no he is not fit to the job but in some countries it may work like KSA in most areas receptionist doesn't need to speak English

English is the official language used in Hotels,  as we care for Guests Satisfaction  we can't afford complains based on misunderstanding, communication.

Person not speaking fluent english does not mean he not fit for the job. the person can be put for concierge or bell desk, give some training. If the person wants to work in recepetion ask him to improve on his language and pull him out from bell desk or concierge.

It depends. If the company has to face foreign delegates or its business is well connected internationaly, english is must for the front desk. But if the company has to deal completely with the local market, fluent in english is not that much necessary.

English is must for a front office person

Yes, if the person holds the valid qualfications, bi-lingual and can promote the neccessary skills then it would be the jugdment of the company or institution to assist in training the individual if need be.