The bilingual-multilingual language processing device (LPD) is a unique symbiosis of two or more languages with a common underlying conceptual base (CUCB) and two or more separate linguistic channels, each of which has less independence than a monolingual system because there is con stant interaction among the channels at each level. Although bilinguals may seem functionally monolingual in most aspects of their language process ing, the constant interaction of the channels of their LPD may result in a lan guage behavior (either overt or covert) distinct from that of the monolin gual (Kasper & Blum-Kulka, 1993; Kecskes, 1998; Yoshida, 1990). In the following chapters we discuss the relation of preverbal thought generated in the multilingual mind to lower and higher level linguistic units such as word, sentence, and discourse. To put it another way, we attempt to explain the processes preverbal thought goes through while it is embodied in words, sentences, and discourse units. Why is an explanation such as this needed in a book about multilingualism, especially about the effect of for eign language (FL) learning on the mother tongue skills? The answer is sim ple: We want to discuss not only the already existing findings but further perspectives for research as well. This endeavor requires to describe how thought and word are interrelated in the multilingual mind.