The aim of this paper is to explore the two kinds of translation problems which result, and to provide a thumb-nail sketch of a theory of meaning structure which enables one to handle such problems as regular and structured phenomena. The first problem that is tackled is that caused when the SL gives zero realisation to referential material which requires overt realisation in the RL. This is the problem of assumed information, or under-translation. The second translation problem discussed is the reverse of the first problem and occurs when referential material which is overtly signalled in the SL is realised by zero in the RL.