When nothing means something:
In morpheme-based morphology, a null morpheme is a morpheme that is realized by a phonologically null affix (an empty string of phonological segments). In simpler terms, a null morpheme is an "invisible" affix. [Wikipedia]
Wikipedia says that examples in English include hiatus and co-operation. I didn't quite get how they have null morphemes. (Well, it is invisible, how am I supposed to see?)
I know that hiatus is the slight pause between two vowels coming together but not in the same syllable. Hiatus itself contains hiatus also. So, is that slight pause a null morpheme? But why do we need to explain with a null morpheme?
Another odd example in English is the invisible notion of singularity and plurality:
- sheep = sheep + -Ø = ROOT ("sheep") + SINGULAR
- sheep = sheep + -Ø = ROOT ("sheep") + PLURAL
I know that the plural form sheep was leveled with the singular in Old English. But why is the need of null morpheme here?
Can you please shed a light on this? Also, is null morpheme a well-accepted concept?