Sentence:  While the phonemes can be very easily stated , no one <WSD>is</WSD> likely to be satisfied with the statement until phonemic occurrences can be related in some way to morphemic units , i. e. until the morphophonemics is worked out , or at least far enough that it seems reasonable to expect success . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)