This paper advances a proposition for the engineering of interactive computer-based environments capable of exhibiting alternative interactive embodiments to cope with diversity in users, interaction platforms and usage contexts. Such systems are referred to as Multiple Metaphor Environments (MME). The theoretical underpinnings of an MME rely on a conception of HCI design as mapping functions in a machine-oriented language (target domain) to symbols in a user-oriented language (source domain), and vice versa. Such a conception, which is rooted in developments in communication theory and the philosophy of language, constitutes the baseline for formulating a proposal for the design of MME. The proposal comprises a set of engineering principles, process-oriented guidelines and design techniques intended to facilitate a detailed account of how interactive systems could be designed to cope with diversity. To aid the articulation of the various properties of MME, we refer to concrete case studies that provide exemplars of novel insights and promising design practices towards the specification of MME.