"
isiXhosa" is not an English word - not yet anyway. Not until it's actually accepted into the Oxford English Dictionary. Until then the few people on the planet actually splicing it in between other English words are doing so at their own risk
Incidentally, new words are added to the Oxford English Dictionary quite frequently. The word "
google", for example, was added not so long ago. To quote their website:
I am fortunate to own the dictionary on CDROM. The full print version (the latest version being the Second Edition but a new print version is currently in the works) comes out in no less than 20 printed volumes. Some people own a compact Oxford English Dictionary which is quite a thick single printed volume, but obviously devoid of most of the historical and etymological background knowledge imparted per word.
Now that we've derailed rather emphatically, let's get back to the topic, up until the word is accepted into the Oxford English Dictionary
as an English word, scholars and academics will not accept the word as English.