Motivated by applications in bioinformatics, we consider the word collector
problem, i.e. the expected number of calls to a random weighted generator of
words of length $n$ before the full collection is obtained. The originality of
this instance of the non-uniform coupon collector lies in the, potentially
large, multiplicity of the words/coupons of a given probability/composition. We
obtain a general theorem that gives an asymptotic equivalent for the expected
waiting time of a general version of the Coupon Collector.