At the time the Hong Kong Immigration Department are asked to verify your eligibility for a permanent identity card, not only must you have been continuously and ordinarily resident in the HKSAR for at least 7 years, but you also need to be able to demonstrate to their satisfaction that you are now permanently settled here.
Settlement in Hong Kong is simply an enquiry of fact.
The Immigration Department will look to such factors as your present and past employment circumstances, do you own and operate a business here, the present location of your wife and children, where your kids are being educated at this time and whether you own property in the HKSAR.
Whilst not mission critical, by any stretch of the imagination, Chinese language ability certainly helps in enabling ImmD to conclude that you are in fact well and truly settled in the HKSAR.
Essentially, the Immigration Department are seeking to assess, on objective grounds, that Hong Kong is now your full time home and as such the declaration that you make as part of your application in respect of you having taken Hong Kong as your only place of permanent residence, is borne out by the actual facts and pattern of your life in Hong Kong.
All told, so long as the regular order of your life points to you being settled in Hong Kong, then this aspect of the acquiring the right of abode is readily and easily satisfied.