The two key questions recurring in the literature on loanword studies are: are there any general patterns of loanword adaptation, and if so, which forces drive the process(es) that result in these patterns. This dissertation readdresses these two questions on the basis of a study of loanword phonology in which Mandarin Chinese (MC) is the recipient language (RL) and English the source language (SL). It argues that factors that have not received much attention in the field have to be taken into consideration. They are input types and adapter types. In this dissertation, the roles of the two factors are put to the test. By investigating both loanword corpus data and extensive experimental results, this dissertation presents an analysis of MC loanword phonology that can account for the intricate adaptation patterns attested in a corpus of loanwords borrowed from English into MC. It moreover shows that, depending on input and/or adapter types, loanword adaptation is driven by one or more of the following grammars: the native RL phonological production grammar, the native RL perception grammar, the RL/SL interlanguage phonological production grammar and the RL/SL interlanguage perception grammar. This dissertation will be of interest to all those working on loanword adaptation, Mandarin Chinese phonology, perception and production in second language acquisition and the role of orthography in linguistics